At a Glance

Founded1987
Renewal dates1992, 1997, 2002, 2007, 2012
Members67
PartnersGordon and Betty Moore Foundation
Disciplines
Condensed matter and quantum physics; atomic, chemical and computational physics; nanomaterials and materials engineering

How can superconductivity transform our society?

The properties of materials have huge influence on our lives: the electrical conductivity of copper, or the magnetic nature of iron, underpin the functioning of modern technology like computers, satellites, our electrical grid and more.

While our understanding of these material properties has been refined over centuries, there are still surprises for those who know where to look. At extreme conditions — for example, very low temperatures or very high pressures — some materials exhibit properties such as superconductivity  or unusual forms of magnetism. If these strange behaviours can be understood and replicated under less extreme conditions, it could lead to technologies far more advanced than those available today.

 

Our unique approach

CIFAR’s Quantum Materials program began in 1987, the same year that the Nobel Prize in Physics was awarded for the discovery of the first high-temperature superconductors. Over three decades, the program has grown to encompass over 60 leading experts from around the world.

By bringing together materials fabrication, experimentation and theory, the program creates a synergistic cycle that pushes the field forward in ways that would not have been possible otherwise.

Members who are experts in fabrication create ultra-pure samples of exotic materials containing novel combinations of chemical elements. Experimentalists, measure the properties of these materials and determine what causes their odd behaviour. Theorists develop new models to explain what is observed in the experiments. Their theories then often  suggest new experiments and fabrication techniques to try.

Damascelli-in-his-lab2-2012
Senior Fellow Andrea Damascelli uses spectroscopic and x-ray scattering techniques to study the low-energy electronic structure of quantum materials

Why this matters

Most hospitals in the developed world have access to a magnetic resonance imaging (MRI) machine. These devices use superconductors — cooled with liquid helium — to create powerful magnetic fields that excite certain atoms within living tissue. MRI is one of the best non-invasive tools for seeing inside the body, eliminating the complications often attached to surgery or x-ray radiation. Each year, hundreds of thousands of patients receive more accurate diagnoses thanks to MRI.

In Japan, magnetically levitated (maglev) trains use superconductors to reach speeds higher than 500 kilometres per hour. Superconductors are also used in the Large Hadron Collider and in other detectors designed to look for exotic particles that help us understand our universe. Some scientists have also proposed using superconductors to create devices that could store energy when it’s cheaper — e.g. at night — and release it when it’s needed.

Yet all current and future uses of superconductors suffer from a similar drawback; the high expense and energy requirements of cooling. Better superconductors that work at higher temperatures could greatly reduce the cost of today’s most advanced technologies and usher in new ones, such as power grids that work at 100 per cent efficiency, with the potential to revolutionize the technological platforms on which our society is based.

 

In depth

While it maintains its original focus on making world-leading advances in superconductivity, the Quantum Materials program has expanded to include research on a wide range of phenomena including new states of matter, unusual forms of magnetism and more.

Superconductivity

Quantum Materials team members have made important progress in this field particularly in understanding why superconductivity is confined to low temperatures. A critical piece of the puzzle fell into place in 2007, when a CIFAR-supported team finally mapped the Fermi surface of a well-known copper-based superconductor and discovered it to be made of small pockets. The unexpected discovery caused a paradigm shift in how scientists thought about the nature of electron behaviour in these materials. It led directly to the recognition of the critical role played by charge density waves — a type of electrical instability, also known as charge ordering ― in suppressing superconductivity.

The advances made in this field provide a great example of CIFAR’s model in action. Senior Fellows Doug Bonn, Walter N. Hardy and Ruixing Liang are among the best in the world at  growering crystals of high-temperature oxide superconductors. Their samples are used by researchers like Program Director and Senior Fellow Louis Taillefer, Senior Fellow Andrea Damascelli, Associate Fellow Cyril Proust and many others. Theorists like Senior Fellow Hae-Young Kee and Associate Fellows Subir Sachdev and Andrew Millis develop models to explain these observations and suggest new experiments that could be tried.

 

Crystal-Revised-Shot
Crystals like these produced in Senior Fellow Bruce Gaulin’s Growth Crystal Lab at McMaster University are used to studyphenomena such as high-temperature superconductivity. Credit: Thomas Van Ryzewk

Cold atoms

Atoms cooled to very low temperatures can become strongly correlated with each other. These systems, in which quantum effects have a big impact, have analogies to the ways electrons move in superconductors. For example, Fellow Joseph Thywissen recently used such a system to look at the demagnetization of an ultracold gas. Measuring the quantum dynamics of strongly interacting ultracold gases can not only offer insight into superconductivity, but also into the exotic states of matter found in neutron stars and other inaccessible places.

Designing new materials

Many members of the QM group focus on designing and building new materials that have unusual quantum properties. Using techniques that deposit individual molecules onto surfaces, researchers can build up materials made of alternating layers that are as little as one atom thick.

 In 2004, Associate Fellow Harold Hwang and his team discovered to their surprise that the interface between two non-conducting oxides behaved like a conductive metal. The discovery generated a flurry of new research, including some that showed such interfaces could behave as superconductors. This remains an active area of study to this day.

Quantum phase transitions

When water freezes or ice melts, we say that the material undergoes a physical phase transition. In a similar way, materials can change from one quantum state to another when subjected to increasingly strong magnetic fields. The driving force behind these phase transitions is quantum fluctuations that exist even at absolute zero.  A recent three-way CIFAR collaboration among Fellow Takashi Imai, Associate Fellow Subir Sachdev and Fellow Graeme Luke showed that these quantum fluctuations persist even at temperatures up to a few dozen degrees above absolute zero. A better understanding of quantum phase transitions could help develop new theories to explain how high-temperature superconductors work.

 

Selected Papers

Ohtomo, A. Hwang, H.Y. (2004) A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427: 423-426

Doiron-Leyraud, N., Proust, C., LeBoeuf, D., Levallois, J., Bonnemaison, J., Liang, R., Bonn, D.A., Hardy, W.N., Taillefer, L. (2007) Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor. Nature 447: 565-568

D. Dalidovich et al., “Spin structure factor of the frustrated quantum magnet Cs2CuCl4,” Physical Review B 73, 18 (2006) doi: http://dx.doi.org/10.1103/PhysRevB.73.184403.

D. LeBoeuf et al., “Electron pockets in the Fermi surface of hole-doped high-Tc superconductors,” Nature 450 (2007): 533-536 doi:10.1038/nature06332.

R. Daou et al., “Broken rotational symmetry in the pseudogap phase of a high-Tc superconductor,” Nature 463 (2010): 519-522 doi:10.1038/nature08716.

R. Comin et al., “Charge Order Driven by Fermi-Arc Instability in Bi2Sr2−xLaxCuO6+δ,” Science 343, 6169 (2014): 390-392 doi: 10.1126/science.1242996.

Fellows & Advisors

Photo of Louis Taillefer

Louis Taillefer

Program Director

Louis Taillefer investigates why some materials exhibit remarkable electronic properties, such as magnetism and superconductivity. In the last decade, he has specialized in superconductors, materials that conduct electricity without any…

Read More >

Fellows

Ian Affleck

Senior Fellow

University of British Columbia

Canada

Yoichi Ando

Associate Fellow

University of Cologne

Germany

Leon Balents

Associate Fellow

University of California, Santa Barbara

United States

Alexandre Blais

Fellow

Université de Sherbrooke

Canada

Immanuel F. Bloch

Associate Fellow

Ludwig-Maximilians University, Max-Planck-Institute for Quantum Optics

Germany

Doug Bonn

Senior Fellow

University of British Columbia

Canada

Collin Broholm

Associate Fellow

The Johns Hopkins University

United States

David Broun

Fellow

Simon Fraser University

Canada

Raffi Budakian

Senior Fellow

University of Waterloo

Canada

Jules P. Carbotte

Senior Fellow

McMaster University

Canada

Robert Cava

Associate Fellow

Princeton University

United States

Andrea Damascelli

Senior Fellow

University of British Columbia

Canada

Eugene A. Demler

Associate Fellow

Harvard University

United States

Steve Dodge

Associate Fellow

Simon Fraser University

Canada

Ian Fisher

Associate Fellow

Stanford University

United States

Joshua Folk

Fellow

University of British Columbia

Canada

Patrick Fournier

Fellow

Université de Sherbrooke

Canada

Marcel Franz

Senior Fellow

University of British Columbia

Canada

Bruce D. Gaulin

Senior Fellow

McMaster University

Canada

Guillaume Gervais

Fellow

McGill University

Canada

Michel J. P. Gingras

Senior Fellow

University of Waterloo

Canada

Walter N. Hardy

Senior Fellow

University of British Columbia

Canada

David G. Hawthorn

Fellow

University of Waterloo

Canada

Jennifer Hoffman

Associate Fellow

University of British Columbia

Canada

Randall G. Hulet

Associate Fellow

Rice University

United States

Harold Y. Hwang

Associate Fellow

Stanford University

United States

Takashi Imai

Senior Fellow

McMaster University

Canada

Stephen R. Julian

Senior Fellow

University of Toronto

Canada

Catherine Kallin

Senior Fellow

McMaster University

Canada

Hae-Young Kee

Senior Fellow

University of Toronto

Canada

Bernhard Keimer

Associate Fellow

Max Planck Institute for Solid State Research

Germany

Yong Baek Kim

Senior Fellow

University of Toronto

Canada

Steven Kivelson

Associate Fellow

Stanford University

United States

Gabriel Kotliar

Associate Fellow

Rutgers University

United States

Karyn Le Hur

Senior Fellow

École Polytechnique and CNRS

France

Lindsay J. LeBlanc

Fellow

University of Alberta

Canada

Ruixing Liang

Senior Fellow

University of British Columbia

Canada

Gilbert Lonzarich

Associate Fellow

University of Cambridge

United Kingdom

Graeme Luke

Senior Fellow

McMaster University

Canada

Joseph Maciejko

Fellow

University of Alberta

Canada

Yoshiteru Maeno

Associate Fellow

Kyoto University

Japan

Andrew Millis

Associate Fellow

Columbia University

United States

Kathryn A. Moler

Associate Fellow

Stanford University

United States

Johnpierre Paglione

Associate Fellow

University of Maryland

United States

Arun Paramekanti

Fellow

University of Toronto

Canada

Cedomir Petrovic

Associate Fellow

Brookhaven National Laboratory

United States

Cyril Proust

Associate Fellow

Laboratoire National des Champs Magnétiques Intenses

France

Subir Sachdev

Associate Fellow

Harvard University

United States

George A. Sawatzky

Senior Fellow

University of British Columbia

Canada

Douglas Scalapino

Associate Fellow

University of California, Santa Barbara

United States

Jeff E. Sonier

Associate Fellow

Simon Fraser University

Canada

Joseph H. Thywissen

Fellow

University of Toronto

Canada

Thomas Timusk

Senior Fellow

McMaster University

Canada

Senthil Todadri

Associate Fellow

Massachusetts Institute of Technology

United States

André-Marie Tremblay

Senior Fellow

Université de Sherbrooke

Canada

John Y. T. Wei

Associate Fellow

University of Toronto

Canada

Hai-Hu Wen

Associate Fellow

Chinese Academy of Sciences

China

Christopher Wiebe

Fellow

University of Winnipeg

Canada

Fei Zhou

Fellow

University of British Columbia

Canada

Advisors

J.C. Séamus Davis

Advisory Committee Chair

Cornell University

United States

Antoine Georges

Advisor

École Polytechnique

France

Richard L. Greene

Advisor

University of Maryland

United States

Andrew Peter Mackenzie

Advisor

Max Planck Institute for Chemical Physics of Solids

Germany

Jochen Mannhart

Advisor

Max Planck Institute for Solid State Research

Germany

Hidenori Takagi

Advisor

Max Planck Institute for Solid State Research

Germany

Global Scholars

Kate A. Ross

CIFAR Azrieli Global Scholar

Colorado State University

United states

Luyi Yang

CIFAR Azrieli Global Scholar

University of Toronto

Canada

Program Timeline

Superconductivity launches

CIFAR launches the Superconductivity program following the spectacular 1986 discovery

A new state of matter

Based on theoretical considerations, CIFAR Fellow Ian Affleck (University of

The big questions for cuprates: Successes and failures of standard approaches to superconductivity

In a definitive review on the Eliashberg approach, the most

Experiment establishes the fundamental pseudogap

A McMaster-University of British Columbia collaboration of CIFAR fellows with

Superconductivity in strange metals

In a conceptual breakthrough, CIFAR associates Claude Bourbonnais and André-Marie

A new theoretical approach

The fact that kinetic and potential energies are comparable in

Spin-charge separation and quasi one-dimensional materials

The idea of spin-charge separation proposed in the context of

The pseudogap state modifies most physical properties

Superconductivity is normally observed in metals, such as aluminum or

New data on superconductivity in crystals

CIFAR fellows Jess Brewer, Rob Kiefl (both University of British

Evidence for a spin-triplet superconductor

CIFAR Senior Fellow and Program Co-Director Louis Taillefer’s group (Université

Challenging assumptions about spins

CIFAR associate fellows John Berlinsky and Catherine Kallin (both McMaster

A new type of quantum criticality

Materials in a quantum critical state exhibit fluctuations that may

A new state called ‘spin ice’

Associate Fellow Michel Gingras’ group at the University of Waterloo

A new spin behaviour

CIFAR Associate Fellow William Buyers (National Research Council of Canada) and

A possible ‘spin liquid’

Theorists Yong Baek Kim (University of Toronto), John Berlinsky and

Program incorporates cold atoms research

The Quantum Materials program begins to incorporate research on cold

A bookmark before the hidden order

CIFAR associate fellows Andrew Peter Mackenzie (Max Planck Institute for

Magnetism and superconductivity linked

Experimentalist Takashi Imai (McMaster University) finds a strong correlation between

A new quantum device

CIFAR Senior Fellow Marcel Franz (University of British Columbia) and Global

Nanowires bring charge drag to the forefront

Using state of the art nanofabrication processes, CIFAR Fellow Guillaume

A theory of the quantum critical point

CIFAR Associate Fellow Subir Sachdev (Harvard University) makes a significant

New phase of matter discovered

New experimental results by CIFAR Associate Fellows Ruixing Liang, Walter

A theory of charge order and d-wave superconductivity

CIFAR Senior Fellow Subir Sachdev (Harvard University) develops a theory

From quantum wire to a quantum faucet

Following a long-standing collaboration with CIFAR Fellow Ian Affleck (University

Credit:

Andrea Damascelli

Electricity encounters no resistance when it moves through superconducting materials. This characteristic can result in strong magnetic fields and levitation

1987

Superconductivity launches

CIFAR launches the Superconductivity program following the spectacular 1986 discovery of superconductivity in copper oxide. Under the direction of Jules Carbotte (McMaster University), it brings together physicists, chemists and materials scientists to study this promising phenomenon.

1989

A new state of matter

Based on theoretical considerations, CIFAR Fellow Ian Affleck (University of British Columbia) proposes a new state of matter, the “flux phase” that is to this day being researched as a candidate phase in cuprates.

1990

The big questions for cuprates: Successes and failures of standard approaches to superconductivity

In a definitive review on the Eliashberg approach, the most sophisticated theory of superconductivity at this time, Program Director Jules Carbotte (McMaster University) sets a roadmap for future experiments and shows that the conventional theory of superconductivity requires a profound re-thinking in order to explain cuprate superconductors.

1993

Experiment establishes the fundamental pseudogap

A McMaster-University of British Columbia collaboration of CIFAR fellows with high-quality crystals demonstrates that superconductivity in cuprates can arise from a new state of matter known as the “pseudogap.” By measuring the optical conductivity, CIFAR Fellow Thomas Timusk demonstrates the fundamental and widespread impact of the pseudogap on the physical properties of cuprates.

1993

First strong evidence for d-wave superconductivity in cuprates

Microwave measurements in crystals of unprecedented quality grown by the groups of CIFAR associates Walter Hardy and Doug Bonn (both University of British Columbia) demonstrate that superconductivity in the cuprates is of d-wave symmetry, a key discovery for understanding these materials.

1995

Superconductivity in strange metals

In a conceptual breakthrough, CIFAR associates Claude Bourbonnais and André-Marie Tremblay (both Université de Sherbrooke) show that quasi one-dimensional organic conductors provide a key example where superconductivity arises from a strange metal where the spin and charge of the electron are separate entities.

Exceptional crystal structures are critical for superconductor research, since even atomic-scale defects can introduce resistivity and lower performance

1995

Superconductivity program renewed

The Superconductivity program passes an expert review and receives a five-year renewal. The reviewers state that the program has established itself at the forefront of research on superconductivity internationally. In the area of materials synthesis, the panel cites Associate Fellows Ruixing Liang, Walter Hardy and Doug Bonn (all University of British Columbia) for their work on single crystals of under-doped yttrium barium copper oxide (YBCO) that lead to the growth of specimens of unprecedented chemical purity and structural quality.  These remarkable samples are at the core of the research of many research groups worldwide, both within the program and outside, and have lead to key discoveries in the field.

1997

A new theoretical approach

The fact that kinetic and potential energies are comparable in cuprates invalidates most standard theoretical approaches and begs for new ones. For that purpose, CIFAR Associate Fellow André-Marie Tremblay (Université de Sherbrooke) and his team devise a new theoretical method especially useful for understanding electron-doped cuprates where the pseudogap arises as a precursor of long-range antiferromagnetic order.

1997

Vortices in high-temperature superconductors

Understanding how a magnetic field penetrates high-temperature superconductors is fundamental to both practical applications and theoretical developments. But the unconventional nature of the superconducting state in the cuprates calls for a new approach. CIFAR fellows Ian Affleck (University of British Columbia) and Marcel Franz (McMaster University) tackled this problem and use their novel approach to explain a wide range of key experiments, including muon-spin relaxation experiments performed at TRIUMF.

1998

Spin-charge separation and quasi one-dimensional materials

The idea of spin-charge separation proposed in the context of the cuprates by P.W. Anderson finds its clearest manifestation in one-dimensional interacting electronic systems. Certain classes of organic charge-transfer salts at finite temperature are well described by this model. CIFAR associate fellows Claude Bourbonnais (Université de Sherbrooke) and Denis Jérome (Université Paris-Sud, Orsay), discuss additional support for the relevance of non-Fermi liquid concepts in the description of the normal state of these organic metals. This prompts interest in gaining more information about the continuous change from a well-defined Luttinger liquid to a Fermi liquid state from which organic superconductivity emerges in these materials.

1999

The pseudogap state modifies most physical properties

Superconductivity is normally observed in metals, such as aluminum or lead. But in cuprates superconductivity appears out of a strange state known as the pseudogap, which is not a metal. CIFAR associates Thomas Timusk (McMaster University) and collaborator Brian Statt (University of Toronto) establish that this state universally impacts on most physical properties of cuprates.

1999

Spin fluctuations as a mechanism of high-temperature superconductivity

Superconductivity appears when electrons couple attractively and for pairs. In conventional superconductors this mechanism involves vibrations of the atomic lattice. But in cuprates, the situation is markedly different. Based on experimental evidence, CIFAR Fellow Jules Carbotte (McMaster University) and collaborators show that antiferromagnetic spin fluctuations are, in fact, the likely source of high-temperature superconductivity.

2000

New data on superconductivity in crystals

CIFAR fellows Jess Brewer, Rob Kiefl (both University of British Columbia), Jeff Sonier (Simon Fraser University) and William Buyers (National Research Council of Canada) implant muons — subatomic particles similar to electrons — into the crystals produced by CIFAR Associate Fellow Ruixing Liang (University of British Columbia) and measure the influence of the crystals on the muons’ spin. They also study the crystals using neutron scattering. These experiments result in new measurements leading to revised views about the magnetic and superconducting features of these materials.

2000

Ferromagnetism found to coexist with superconductivity

CIFAR Associate Fellow Michael Walker (University of Cambridge) and his collaborators find the strongest type of magnetism responsible for ordinary magnets, known as ferromagnetism, can coexist with superconductivity in certain materials. This contradicts a long-held belief that these two qualities were incompatible.

2000

The emblematic phase diagram of layered organic superconductors

CIFAR associates Claude Bourbonnais (Université de Sherbrooke) and Denis Jérome (Université de Paris-sud, Orsay) unveil the phase diagram of organic superconductors. It clearly establishes the coexistence of superconductivity and magnetism, and highlights the importance of Mott physics, a key paradigm in quantum materials with far-reaching implications for cuprates and beyond.

2001

Evidence for a spin-triplet superconductor

CIFAR Senior Fellow and Program Co-Director Louis Taillefer’s group (Université de Sherbrooke) finds evidence that the perovskite oxide crystal Sr2RuO4 has an unconventional character when cooled low enough to become a superconductor. It’s called a p-wave spin-triplet superconductor, and the experimental evidence backs up years of theoretical predictions. The study uses Sr2RuO4 samples produced by Associate Fellow Yoshiteru Maeno (Kyoto University).

2002

Challenging assumptions about spins

CIFAR associate fellows John Berlinsky and Catherine Kallin (both McMaster University) publish calculations about cuprates that shed new light on spin-lattice relaxation, which is the process by which vibrating electrons — meaning those in an excited magnetic state — return to equilibrium. They find that spin-lattice relaxation is dependent on the frequency of spin vibrations and temperature in ways that challenge previous assumptions that fluctuations in the pattern of directions that spins point in certain magnets, (known as antiferromagnetic spin fluctuations) cause spin-lattice relaxation in the mixed state.  

Several associate fellows in the program possess outstanding skills in crystal growth. They produce the high-quality samples needed by experimental researchers to study the nature of superconductivity

2002

Single crystals for neutron scattering experiments

CIFAR associate fellows William Buyers (National Research Council of Canada), Robert Birgeneau (University of California, Berkeley) and Ruixing Liang (University of British Columbia) ccollaborate to grow large crystals of cuprates for neutron experiments in order to probe the electronic and magnetic properties in their bulk. Such experiments provide answers about the transformations that occur from a robust superconductor to its polar opposite — a total insulator. These, in turn, feed directly theorists such as CIFAR associate fellows Steven Kivelson (Stanford University), Ian Affleck (University of British Columbia), André-Marie Tremblay, and Hae-Young Kee.

At absolute zero, cerium-cobalt-indium5 (CeCoIn5) fluctuates between superconducting behaviour (SC, grey) and a Fermi liquid state (FL, blue)

2003

A new type of quantum criticality

Materials in a quantum critical state exhibit fluctuations that may promote novel and exciting states of matter. Unconventional superconductivity is one of them. CIFAR Senior Fellow and Program Co-Director Louis Taillefer (Université de Sherbrooke) and his group discovers a new type of quantum criticality in the alloy Cerium-Cobalt-Indium 5, which appears to be associated with the superconducting transition itself.. In a different alloy made of Manganese and silicon, CIFAR Fellows Stephen Julian (University of Toronto) and Taillefer find that the quantum critical state persist over an unusually large range of parameters, suggesting the existence of a new quantum phase of matter.

CIFAR Associate Fellow Stephan Julian

2003

A hint at a quantum phase transition

A team at Cambridge University in collaboration with CIFAR Associate Fellow Stephen Julian (University of Toronto) and Louis Taillefer (Université de Sherbrooke) finds the first instance of quantum criticality that persists far away from the quantum critical point. The discovery could suggest the existence of a new quantum phase of matter.

2003

Magnetic probe studies ultra-thin films

CIFAR Associate Fellow Rob Kiefl (University of British Columbia) and his collaborators at TRIUMF in Vancouver develop a magnetic probe to study ultra-thin films and interfaces. It allows them to perform magnetic resonance without applying a magnetic field, which is important for studies on exotic magnetism and superconductivity.

CIFAR Associate Fellow Michel Gingras

2004

A new state called ‘spin ice’

Associate Fellow Michel Gingras’ group at the University of Waterloo develops a quantitative theory explaining the behaviour of a new class of magnetic material called "spin ice". In spin ice, the amount of torque atoms experience under a magnetic field — or magnetic moments — do not freeze under very low temperatures. This is similar to how protons behave in ice. The researchers design various experiments to investigate the effects of applied magnetic field on spin ice and they observe a number of unexplained phenomena. For example, they find phase transitions with a field strength up to 80 times larger than the strength of the magnetic interactions between spins, regardless of how strong a magnetic field they apply — a puzzling result. Gingras develops a theory attempting to explain these results.

Sample of an yttrium barium copper oxide crystal produced by CIFAR associate fellows Liang, Bonn and Hardy

2004

Homing in on superconductivity’s cause

CIFAR associate fellows Doug Bonn, Ruixing Liang and Walter Hardy (all University of British Columbia) discover a new universal trend between the temperature at which superconductivity occurs and the superfluid density in cuprates, shedding new light on the mechanism responsible for superconductivity.

CIFAR Associate Fellow Timothy Timusk

2004

Magnetic resonance ruled out

CIFAR Associate Fellow Thomas Timusk (McMaster University) and collaborators show experimentally that magnetic resonance does not cause superconductivity, ruling out one of the major candidate theories for the phenomenon. Their scaling relation applies to several materials manipulated in various ways.

2004

Pseudogap and strong interactions

CIFAR associate André-Marie Tremblay (Université de Sherbrooke), with his colleague D. Sénéchal, using newly developed Quantum Cluster methods, demonstrate that the pseudogap can arise purely from strong interactions, without symmetry breaking. They also propose an argument for why the strength of correlations is weaker in electron-doped cuprates than in hole-doped ones.

2004

Pseudogap as a precursor of long-range order

CIFAR Associate André-Marie Tremblay (Université de Sherbrooke) and his team make detailed theoretical comparisons with experimental results to show that in electron-doped cuprates, the pseudogap can be understood as a two-dimensional finite temperature precursor of antiferromagnetic long-range order. Since breaking of a continuous symmetry is prohibited in two dimensions by a theorem, it is clearly the coupling to the third dimension that finally gives rise to long-range order.

2005

A new spin behaviour

CIFAR Associate Fellow William Buyers (National Research Council of Canada) and his collaborators discover a new spin behaviour at the interface between superconductivity and magnetism in cuprates. This observation results from collaborations with the University of Toronto, University of British Columbia, NRU Chalk River Laboratories, and the provision of cold neutrons at numerous international facilities. Fellows report that success of this national and international initiative is largely due to the exchange of ideas via CIFAR interactions.

2005

Quantum dots observed

CIFAR Senior Fellow Ian Affleck (University of British Columbia) and others use methods borrowed from string theory to find the exact low temperature behaviour of three chemically bound molecules — a trimer — of quantum dots. Quantum dots are tiny islands of electrons fabricated in semi-conductor wafers that exhibit novel electronic properties with potential significance for future technologies. In some configurations, they violate the “Fermi liquid” paradigm which usually applies to conduction electrons at low temperatures, exhibiting strong quantum entanglement between the quantum dots and the electrons in the attached leads. Their solution shows that the trimer is a uniquely favourable system for observing this special behaviour.

The triangular structure of the NIGAS material produces ideal conditions for spin disorder

2005

Material with spin disorder found

The spins of electrons in most materials order into a particular pattern pointing in opposite directions when cooled to a certain temperature. CIFAR Associate Fellow Yoshiteru Maeno (Kyoto University) and his collaborators find a material in which this does not happen. It is a layered insulator with a triangular arrangement of atoms, the optimum geometry for preventing this ordering, known as antiferromagnetism.  

Representation of a quantum spin liquid

2006

A possible ‘spin liquid’

Theorists Yong Baek Kim (University of Toronto), John Berlinsky and Catherine Kallin (both McMaster University), all CIFAR associate fellows, investigate a 3D material that has shown hints of behaving like a quantum spin liquid. A quantum spin liquid is a state of matter, called a liquid because it is disordered compared to other quantum states — similar to how water is disordered compared to ice. They identify the material as a promising candidate to reach, or nearly reach, the spin liquid state.

2006

A new quantum critical point discovered

Program Director Louis Taillefer’s group (Université de Sherbrooke) discovers a new quantum critical point in the compound CeCoIn5, a material in which CIFAR Associate Fellow Zachary Fisk (University of California, Irvine) identified superconductivity in 2001. It is one of few known materials whose quantum criticality can be tuned with a magnetic field. Taillefer’s group is the first to investigate quantum criticality with heat transport, a powerful technique governed by a universal law of metals. Termed the Wiedemann-Franz law, it states that charge and heat conduction are strictly equal at absolute zero temperature. Taillefer’s group finds that the Wiedemann-Franz law holds in CeCoIn5, even though other signatures of Fermi-liquid theory break down.

Credit: Proceedings of the National Academy of Sciences

Representation of a stripe-ordered phase. The arrows represent the magnetic or spin order, and the blue scale represents the charge density

2006

Superconductors give way to stripes

CIFAR Associate Fellow Steven Kivelson (Stanford University) builds upon his seminal work on stripes, which refers to a phase transition in which the spins of electrons in materials under certain conditions form striped patterns. He explores possible manifestations of stripes in cuprate superconductors and finds that when cuprates are on the edge of superconductivity, they begin to fall into an ordered ‘stripe’ phase. The highest transition temperatures occur in this unstable state. Kivelson’s body of work establishes him as the leading theorist on stripes.

2006

Pseudogap and short-range spin correlations

A collaboration between the teams of CIFAR fellows André-Marie Tremblay’s (Université de Sherbrooke) and Gabriel Kotliar’s (Rutgers University) groups demonstrates with Cellular Dynamical Mean-Field Theory that the pseudogap state can arise from short-range spin correlations without symmetry breaking, reinforcing earlier 2004 results about the importance of the proximity of the Mott insulator for pseudogap behaviour.

2006

A revolutionary approach to the problem of strongly interacting electrons

CIFAR Associate Fellow Andrew Millis (Columbia University) and his group develop a new Quantum Monte Carlo method to attack the problem of strongly correlated electrons that must be solved to handle theoretical models of cuprates.

2007

Program incorporates cold atoms research

The Quantum Materials program begins to incorporate research on cold atoms. Systems of atoms cooled to very low temperatures that become strongly correlated with each other have analogies to the ways in which electrons move in superconductors. Studying them can help discover and understand new states of matter and quantum materials.

Quantum oscillations in the superconductor YBCO

2007

Quantum oscillations breakthrough

Quantum oscillations are observed in the superconductor YBCO for the first time, by CIFAR associate fellows Doug Bonn, Ruixing Liang and Walter Hardy (all University of British Columbia) and Program Director Louis Taillefer (Université de Sherbrooke). Performing the experimental technique used to induce and measure quantum oscillations is a major breakthrough that shows the features of this copper-oxide’s Fermi surface — an abstract interface that is important for predicting the thermal, electrical, and other characteristics of certain materials. They find that YBCO’s Fermi surface contains small closed pockets, different from the mysterious arcs previous techniques observed. Six months after this breakthrough, the same team made a startling discovery: these small Fermi pockets do not contain holes but electrons. This ground-breaking work shows that there is a hidden phase that competes with superconductivity. It causes a paradigm shift in the field and sparks a flurry of research activity worldwide and within the program. Louis Taillefer’s quantum oscillations were chosen as one of the top ten discoveries in 2007.

2007

A tunable interface

CIFAR Advisor Jochen Mannhart (Max Planck Institute for Solid State Research) and his collaborators observe a superconducting interface state that can be tuned electrostatically. This discovery follows the important 2004 finding that the interface between two insulating oxides (SrTiO3 and LaAlO3) is a metal. It advances a major effort in the Quantum Materials program to artificially design new quantum materials, often layer by layer, with the potential for new and revolutionary properties.

2007

Transmitting quantum information with superconductors

CIFAR Fellow Alexandre Blais (Université de Sherbrooke) studies how superconductors can be used to make a quantum computer. He and collaborators at Yale University invent a way to transmit quantum information from one qubit to another over large distances using a superconducting circuit. Previously, information was stored in superconducting qubits, but not transmitted. Québec Science magazine chooses it as one of 2007’s top 10 discoveries by a Quebec scientist.

2008

A bookmark before the hidden order

CIFAR associate fellows Andrew Peter Mackenzie (Max Planck Institute for Chemical Physics of Solids) and Cyril Proust (National Center for Scientific Research)detect quantum oscillations in an overdoped high-temperature cuprate superconductor, providing providing clear evidence for a Fermi surface in the overdoped regime of cuprates. The measured Fermi surface corresponds to that anticipated in calculations, and is in stark contrast with that seen on the underdoped side, proof that a fundamental transformation occurs between the two regimes.

CIFAR Fellow Guillaume Gervais

2008

A new quantum phase discovered

Working with one of the purest semiconductor chip materials, CIFAR Fellow Guillaume Gervais (McGill University) and his team discover a new quantum phase of electrons, called a quasi-3D Wigner crystal. The team discovers this superconductor by exposing it to the most powerful continuous magnetic field in the world in a device cooled to nearly absolute zero.

2008

A new type of electron solid discovered

In a series of careful measurements, CIFAR Fellow Guillaume Gervais’ (McGill University) group discovers a new type of electron solid at high magnetic fields. They make the discovery while studying states that are important for building a practical quantum computer, known as fractional quantum Hall states.

2008

The superconducting state of the new iron-based high-temperature superconductors

CIFAR Associate Fellow Douglas Scalapino (University of California, Santa Barbara) and his team perform theoretical calculations that help interpret neutron scattering measurements that aim to understand the superconducting state of the just-discovered iron-pnictide high-temperature superconductors.

Credit: Takashi Imai

Crystal structure of BaFe2As2, a semimetal that can superconduct when cobolt replaces some of its Fe atoms.

2009

Magnetism and superconductivity linked

Experimentalist Takashi Imai (McMaster University) finds a strong correlation between magnetism and superconductivity using nuclear magnetic resonance to study crystals. The finding provides new evidence that the glue which binds electrons together into pairs, allowing them to transmit energy with zero resistance, is magnetic in origin.

2009

Artificial 2D superconductors

CIFAR Associate Fellow Harold Hwang (Stanford University) discovers a new way to create artificial two-dimensional superconductors, using complex oxide super-lattices, which are so electrically clean that 2D quantum effects can be seen in both the normal and superconducting state. These studies are complemented by CIFAR collaborations with CIFAR Senior Fellow George Sawatzky (University of British Columbia) and Global Scholar Hiroki Wadati (University of Tokyo) to design the interface electronic structure.

Credit: Graeme Luke

CIFAR researchers studied the behaviour of electrons at extremely low temperatures in the hidden-order state

2009

A theory of the hidden order

CIFAR Associate Fellow Gabriel Kotliar (Rutgers University) and a collaborator propose a promising theory explaining the order parameter of the “hidden order” phase. In the class of metals known as heavy fermion systems, cooling to extremely low temperatures causes electrons to behave as if they had masses up to 1,000 times heavier than their nominal mass. The “hidden order” phase is another strange phenomenon in which the bulk properties of the material change sharply. It occurs in the heavy fermion compound uranium ruthenium silicide (URu2Si2). Following the publication of Kotliar’s theory, CIFAR Fellow Graeme Luke (McMaster University) produces high quality single crystals of URu2Si2 , and Advisor J.C. Seamus Davis (Cornell) uses a cryogenic scanning microscope to watch the behaviour of the electrons in these crystals as they are cooled to increasingly low temperatures. The team observes the heavy electrons and how their velocities change, both when they enter the heavy fermion state and when they undergo the transition to the hidden-order state, showing just how these states evolve with decreasing temperature.

2009

Linear temperature dependence of resistivity and superconductivity

CIFAR fellows at the Université de Sherbrooke and Université de Paris-sud, Orsay demonstrate that linear temperature dependence of resistivity and unconventional superconductivity are intimately linked not only in cuprates but also in apparently quite different materials. They have in common the proximity to an antiferromagnetic phase and, in the case of the organics, the connection can be made theoretically quite clearly.

Representation of the inverse spin-galvanic effect

2010

A new quantum device

CIFAR Senior Fellow Marcel Franz (University of British Columbia) and Global Scholar Ion Garate (Université de Sherbrooke) explore an effect that could be used in future applications such as storing information in computer memory without losing energy. It is called the inverse spin-galvanic effect, and they propose a device to achieve it consisting of a monolayer-thin, insulating ferromagnet with a soft perpendicular anisotropy deposited on the surface of a topological insulator.

2010

Discovery of an order that coexists with superconductivity

Program Director Louis Taillefer’s (Université de Sherbrooke) discover a new property that may reveal the fundamental mechanism responsible for superconductivity in the cuprates. The researchers conduct measurements on crystals of yttrium barium copper oxide (YBCO) provided by CIFAR associate fellows Doug Bonn, Ruixing Liang and Walter Hardy (all University of British Columbia). They find that the electrons in these materials have a spontaneous tendency to align, which strongly suggests that some form of hidden and probably magnetic order co-exists with superconductivity.

CIFAR Associate Fellow Ian Fisher

2010

2D quantum oscillations measured

CIFAR Associate Fellow Ian Fisher (Stanford University) and collaborators succeed in measuring quantum oscillations coming from the 2D surface state, in fields up to the limit of accuracy at quantum scales. Their work paves the way for experiments probing fractional quantum Hall behaviour, which is important for building a practical quantum computer.

2010

The insulating phase’s influence

Cuprates are obtained by adding carriers, i.e. doping, insulating parent compounds. The insulating behaviour comes from strong electron repulsion. But how far does the influence of this insulating state extend? CIFAR Associate André-Marie Tremblay (Université de Sherbrooke) and his team using Cellular Dynamical Mean-Field Theory show that signatures of the “Mott” insulator manifest themselves for dopings as large as 12 per cent.

2011

Nanowires bring charge drag to the forefront

Using state of the art nanofabrication processes, CIFAR Fellow Guillaume Gervais (McGill University) and his team at McGill University successfully create one of the smallest electronic circuits ever. It is actually two independent circuits separated by only 10 nanometers are coupled on a single chip, allowing a study of how charges flowing through one wire interact with those of the other wire. This phenomenon, known as Coulomb drag, is usually understood in terms of a friction-like interaction between the charges, but as Gervais and colleagues showed with their unique device, more subtle effects are also at play.

CIFAR Advisor Hidenori Takagi at the October 2014 Quantum Materials program meeting

2011

Stripe order found in YBCO

Program Director Louis Taillefer (University of Sherbrooke), Fellows Doug Bonn, Walter Hardy and Ruixing Liang (all University of British Columbia) and Associate Cyril Proust (Laboratoire National des Champs Magnétiques Intenses – Toulouse) made a major breakthrough in 2007 when they discovered that electrons in a specific cuprate superconductor, yttrium barium copper oxide (YBCO), undergo a profound transformation of their metallic state, besides the appearance of superconductivity itself. In 2011, they find that the transformation involves a state of matter called “stripe order” – a wave-like pattern of electron charges. They reach this conclusion by comparing the thermo-electric properties of YBCO with those of another cuprate, Eu-LSCO, in collaboration with Advisor Hidenori Takagi (University of Tokyo). The implication is that stripe order likely plays a key role in controlling the critical temperature at which superconductivity occurs. This information strikes near to the heart of whether it will be possible to produce superconductivity at room temperature.

Credit: Graeme Luke

STM imaging of heavy fermion behaviour

2011

New insights on the destruction of heavy fermion systems

Experiments by Fellow Graeme Luke (McMaster University), Advisor J.C. Séamus Davis (Cornell University) and colleagues reveal what happens when an exotic state of electronic matter called “heavy fermions” is destroyed. They study a known heavy fermion compound of uranium, ruthenium and silicon. Electrons flowing through this material briefly interact with the magnetic electrons surrounding the uranium atoms, slowing them down and making them seem “heavy.” Theory has long predicted that replacing magnetic uranium atoms in this compound with non-magnetic atoms would create “Kondo-holes” — another exotic quantum state — at each substitution site, destroying the heavy fermion system. To find out what this behaviour would look like, Luke created high-quality compound samples, replacing several uranium atoms with nonmagneticthorium. Then Davis examines them using a new technique called spectroscopic imaging STM, which he developed to directly visualize electron structure at the atomic scale. The team is able to “see” Kondoholes for the first time, and discover that around each thorium atom, the stability of heavy fermions decays in a wave-like fashion, widely disrupting the flow of electrons through the material.

Credit: Kathryn Moler

Nanoscale patches of magnetism near the interface of two nonmagnetic oxides

2011

Magnetism imaged at an interface

Associates Kathryn Moler and Harold Hwang (both Stanford University) and their students discover a unique co-existence of magnetism and superconductivity – two electronic states that normally are highly antagonistic to one another. The work leading up to this surprising result began with Hwang’s team creating a new material sample composed of two non-magnetic insulators sandwiched together: lanthanum aluminate and strontium titanate. Sometimes, the layer of atoms where two joined materials meet displays properties that are radically different from those found in the bulk of either material. With this in mind, Moler’s group scans the new sample using a special kind of microscope that can image traces of magnetism. The resulting images revealed an intimate mix of superconducting and magnetic regions at the interface between the two insulators – a co-existence that has not been seen before. The discovery creates an opportunity to further explore how these normally incompatible states are interacting in this material. Further research may also lead to the ability to manipulate the electronic properties of these materials for technological applications.

Credit: Subir Sachdev

The highest and lowest values of charge density waves alternate across material structures

2012

A theory of the quantum critical point

CIFAR Associate Fellow Subir Sachdev (Harvard University) makes a significant theoretical advance in understanding the central organizing principle of most unconventional superconductors — the antiferromagnetic quantum critical point. One of the fascinating outcomes of his theory is the discovery that electrons near this point have two natural instabilities: an expected d-wave pairing state and an unexpected special kind of “d-wave-like” charge order. An exciting possibility from this work is that the charge order observed experimentally in the cuprate YBCO may in fact be this second instability.

2012

Charge density waves discovered in YBCO

In a major discovery, two groups directly observe competition between a phenomenon known as charge density waves and superconductivity in the copper-oxide YBCO. One of the research teams includes CIFAR associate fellows Doug Bonn, Ruixing Liang and Walter Hardy (all University of British Columbia).

2012

A new magnetic phase diagram

CIFAR Associate Fellow Yoshitero Maeno (Kyoto University), Senior Fellow Graeme Luke (McMaster University) and collaborators produce a new magnetic phase diagram of the unconventional superconductor (Sr,Ca)2RuO4. Their findings about magnetism in this material contradict previously held views and show the proximity of superconductivity to the competing phase known as static magnetic order.

2013

New phase of matter discovered

New experimental results by CIFAR Associate Fellows Ruixing Liang, Walter Hardy and Doug Bonn (all University of British Columbia) and collaborators at Los Alamos National Laboratory prove that the “pseudogap” — a partial energy gap between quantum states that appears at a temperature well above the onset of superconductivity — is a distinct thermodynamic phase of matter. The researchers use high-precision resonant ultrasound measurements on copper oxide samples produced by the CIFAR team to reveal the effects that resolve this long-standing mystery.

2013

Computer simulations solve model for the pseudogap state

The pseudogap state appears as a broad crossover in a number of experiments on hole-doped cuprates before superconductivity appears at lower temperatures. CIFAR Senior Fellow André-Tremblay (Université de Sherbrooke) and his team show that most of these features find their natural explanation in the one-band Hubbard model when interactions are strong enough. The model is solved with cluster generalizations of dynamical mean-field theory that require large scale computer simulations.

Program Director Louis Taillefer

2013

Pressure found to change superconductivity

Program Director Louis Taillefer’s (Université de Sherbrooke) group makes a surprising discovery about how pressure affects the transition to superconductivity in an iron-based superconductor. They find that adding pressure decreases the onset temperature of superconductivity to a point, but after a certain amount of pressure is applied, it suddenly switches to increasing the onset temperature. The finding suggests there is a transition from one pairing state to another. Researchers think this could be experimental evidence for competing pairing states previously theorized by CIFAR Associate Fellow Andy Millis (Columbia University).

2013

Magnetic spin interactions in a spin ice

CIFAR senior fellow Bruce Gaulin (McMaster University) conducts experiments on ytterbium titanate. Using neutron scattering, he determines the microscopic parameters that describe its magnetic spin interactions. Senior Fellow and theorist Michel Gingras (University of Waterloo) then joins him in reviewing this first available quantitative data. They discover that these interactions allow for a detailed and natural explanation of the thermodynamic properties of this quantum spin ice material. This research advances a long-term CIFAR collaboration between theorists and experimentalists in this area.

2013

Superconductivity, pseudogap and the physics of strong interactions

CIFAR Associate Fellow Andrew Millis (Columbia University) and CIFAR Senior Fellow André-Marie Tremblay’s (Université de Sherbrooke) group demonstrate that much of the temperature-doping phase diagram of high-temperature superconductors can be understood from cluster generalizations of dynamical mean-field theory.

2014

A theory of charge order and d-wave superconductivity

CIFAR Senior Fellow Subir Sachdev (Harvard University) develops a theory explaining charge order and d-wave superconductivity as two natural and intimately related instabilities of an underlying antiferromagnetic quantum critical point — the organizing principle of most unconventional superconductors. This theory explains why modulations of the electronic charge density rise slowly as copper-oxides cool, as experiments have observed with x-ray diffraction.

CIFAR Senior Fellow Andrea Damascelli

2014

Charge ordering found across cuprates

CIFAR Senior Fellows Andrea Damascelli and George Sawatzky (both University of British Columbia), CIFAR Associate Bernhard Keimer (Max Planck Institute for Solid State Research) and other collaborators in the United States and Japan shed light on a phase that appears to compete with superconductivity called charge ordering, in which electrons organize themselves in a wave-like pattern. The researchers observe that the “charge density waves” associated with charge ordering are consistent across different types of cuprate materials, suggesting the existence of a universal charge order common to all cuprates. The researchers use different experimental techniques to detect and measure these tiny ripples in electron charge distribution and prove the complementary power of these tools to probe the subtleties of these features.

2014

One-dimensional wire confirms theory

CIFAR Fellow Guillaume Gervais (McGill University) creates a device that confirms the theoretically predicted “Luttinger liquid” state. A Luttinger liquid is the quantum state that results when electrons are confined in a line with no freedom to move anywhere other than back and forth. The researchers create the device on a chip that confines electrons into two quantum wires, separated by only 15 nanometers, or roughly 150 atoms. The device allows the researchers to confirm theoretical predictions by measuring the “friction” between the two circuits. This effect was predicted to increase sharply below a certain temperature if a Luttinger liquid is formed. The team demonstrates that the increase does occur at a temperature of about 1.6 Kelvin, which is close to absolute zero. The result could help in developing practical applications as the building block of modern computers and other electronic devices continue to shrink.

2014

A lower speed limit to the diffusion of spins

CIFAR Fellow Joseph Thywissen (University of Toronto) and his team trap ultracold gas atoms in a low-pressure vacuum, manipulating the spins with an effect that’s regularly used in hospitals or MRIs, called a spin echo. They measure the strength of interactions between atoms as they twist and untwist the direction of the spins. At first, the atoms are not interacting, but in a millisecond they switch to strongly interacting and their spins are correlated, suggesting an alteration to the atoms’ magnetism. The team finds that diffusion is causing the change. They crank up the interactions as high as possible to slow down the process of diffusion and find that it does not reach zero. Instead, it has a lower speed limit that hints at a universal principle about spin transport.

2014

Choosing a direction

There are many signs that electrons in cuprates and pnictides might prefer to move along one direction more than another, but do not manage to choose, since no direction is favored a priori. The fluctuations between the two directions, known as nematic fluctuations, are a possible candidate for unconventional superconductivity observed in these compounds, as demonstrated by Associate Fellow Douglas Scalapino (University of California, Santa Barbara) and his collaborators.

2015

From quantum wire to a quantum faucet

Following a long-standing collaboration with CIFAR Fellow Ian Affleck (University of British Columbia),  Guillaume Gervais’ lab successfully draws superfluid helium through the smallest channel yet — only a few tens of atoms across in width. When cooled to temperatures near absolute zero, helium begins to flow freely without viscosity, a state known as a superfluid. Most fluids flow faster when forced through a narrow space, but quantum theory predicts that helium will change its state and slow down if it is confined to one dimension. The researchers prove this experimentally, which brings them to the threshold of observing a theoretical state of matter known as a Luttinger liquid. A Luttinger liquid describes the quantum state of electrons confined in a line, only able to move back and forth. Theory suggests the underlying physics in this state changes completely.

P-F. Duc et al, “Critical flow and dissipation in a quasi–one-dimensional superfluid,” Science Advances 1, 4 (May 2015): e1400222 (2015).

Credit: Selbysha

A molecular representation of phosphorene

2015

Phosphorene shows promise for transistors

CIFAR Fellow Guillaume Gervais (McGill University), in collaboration with Thomas Szkopek’s group, observe quantum oscillations in a material made of a single layer of black phosphorus atoms, known as phosphorene, using a powerful magnet at the National High Magnetic Field Laboratory. Phosphorene is lauded as a promising new engineering material that could replace silicon for building transistors in electrical circuits. Another material, graphene, has also been studied as a candidate for transistors, but it lacks certain properties to work naturally. Unlike graphene, phosphorene is a semiconductor, which makes it easier to control its conductivity.

Ideas Related to Quantum Materials

Quantum Materials | News

Building stable qubits in diamonds

The potential power of a quantum computer comes from the qubit – a unit of information which quantum physics allows...

Bio-inspired Solar Energy | Commentary

Canada’s role as a clean tech research leader

Last month I met with Dr. Mario Molina, the chemist who more than 40 years ago made the Nobel Prize-winning...

Cosmology & Gravity | Commentary

Making waves in interdisciplinary research

One hundred years ago, Albert Einstein predicted that gravity could propagate in the form of gravitational waves, bending the fabric...

Quantum Materials | News

Probing the symmetry of superconductivity at the atomic level

Electron orbitals can exhibit surprising and unexpected patterns in superconducting cuprates, according to the latest finding by Waterloo physicists David...