Milestones in Superconductivity at the University of Illinois
Our current multi-pronged research efforts in the field of superconductivity are built on a rich history, beginning with the discovery of Cooper pairs and the Bardeen–Cooper–Schrieffer theory of superconductivity (BCS Theory). Today, Illinois physicists continue our legacy of scientific discovery in this field so critical to the development of tomorrow's technologies.
In 1911, while studying the electrical resistance of solid mercury at cryogenic temperatures, Dutch scientist Heike Kamerlingh Onnes discovered superconductivity when that resistance disappeared. Scientists around the globe joined in the effort to understand and characterize this emergent phenomenon. In the 1950s at the University of Illinois Urbana-Champaign, John Bardeen, Leon Cooper, and J. Robert Schrieffer made one of the greatest discoveries of their time in the field of superconductivity: the BCS theory explained the microscopic origins of superconductivity. This seminal work cemented Illinois' position at the leading edge of condensed matter physics .
Below you will find a timeline marking the key research contributions and milestones in superconductivity at Illinois.
Charles P. Slichter, a pioneer of nuclear magnetic resonance research, joins the Department of Physics at Illinois at the invitation of F. Wheeler Loomis. Slichter would go on to make ground-breaking discoveries to elucidate the mechanisms of superconductivity, including the first experimental confirmation of electron pairing, central to the Bardeen–Cooper–Schrieffer (BCS) theory and the behavior of high-temperature superconductors.
Dillon E. Mapother joins the faculty as an instructor (promoted to assistant professor in 1951). His first assigned duty is to set up cryogenic capabilities for the department’s new research program in low-temperature physics, and he oversees the installation of a helium distribution and recovery system. He would go on to contribute to the development of novel experimental methods and instrumentation for the study of superconductivity.
1949John Bardeen joins Illinois. He establishes two major research programs; one in the Physics Department focusing on theoretical aspects of macroscopic quantum systems, particularly superconductivity and quantum liquids, and one in the Electrical Engineering Department dealing with both experimental and theoretical aspects of semiconductors.
Charles P. Slichter, along with H.S. Guotwsky and D.W. McCall, discovers indirect spin-spin coupling, known as J-coupling, which enables structural information about molecules to be deduced from their nuclear magnetic resonance (NMR) spectrum. The trio would later receive the American Chemical Society’s Breakthrough Award for their discovery.
1951David Pines and his mentor at Princeton University, David Bohm, develop the Bohm–Pines theory, the quantum theory of the uniform electron gas. This work would lead to the discovery of the random phase approximation to electron gases. Later the same year, Pines joins Illinois as a postdoc under John Bardeen.
1952J. Robert Schrieffer begins graduate studies under John Bardeen.
John Bardeen is elected to the National Academy of Sciences.
David Pines and John Bardeen show that scattered electrons in a crystal lattice can be attracted to each other. This interaction (the Bardeen–Pines Hamiltonian) is a key element of the BCS theory of superconductivity.
Inspired by David Pines, Charles P. Slichter and graduate students Thomas R. Carver and Robert Schumacher measure electron spin contribution to the magnetic susceptibility of metals for the first time. The experiment opens an important door to understanding interactions of electrons in metals, a problem at the theoretical forefront at the time.
1954John Bardeen and David Pines extend the Bohm–Pines collective description of electron interactions to include the electron-phonon interaction, showing that this interaction can mediate an attractive electron-electron interaction, a key element in the Bardeen–Cooper–Schrieffer (BCS) theory of superconductivity.
Leon Cooper becomes a postdoc under John Bardeen.
David Pines leaves Illinois to join Princeton faculty.
1955Dillon E. Mapother builds a specially designed cryostat that allows precise ballistic induction measurements under conditions of exceptionally good temperature stability, down to temperatures of about 0.8 K. He and his students use the instrument to make precise measurements of the superconducting transition of aluminum, published in Physical Review in 1958.
Leon Cooper discovers “Cooper pairs,” the phenomenon that electrons are attracted to each other in superconductors when normally they repel each other.
1956J. Robert Schrieffer realizes he can combine the knowledge of Cooper pairs with the variational approach used by Sin-Itiro Tomonagato to address the so-called pion-nucleon problem in high-energy physics. Using this method, Schrieffer solves what is now known as the gap equation for superconductivity, showing that Cooper pairs can be extended to the entire set of electrons in a metal.
John Bardeen, Leon Cooper, and J. Robert Schrieffer publish “Theory of Superconductivity.”
1957At the Bohr Institute, David Pines collaborates with Aage Niels Bohr and Ben Roy Mottelson, introducing them to the theory of superconductivity by showing the relevance of these concepts to pairing in nuclear physics. The paper by Bohr, Mottelson, and Pines on a possible analogy between the excitation spectra of nuclei and those of the superconducting metallic state represents the first-ever application of BCS concepts to nuclear physics.
David Pines, at the invitation of J. Robert Oppenheimer, spends the next year as a visiting member of the Institute for Advanced Study at Princeton. He collaborates on developing a microscopic understanding of superfluid 4He.
1958Donald M. Ginsberg joins the Department of Physics as a research associate and associate professor after completing his graduate work with fellow superconductivity researcher Michael Tinkham at the University of California, Berkeley. Ginsberg builds off his thesis work, “Far Infrared Transmission Through Superconducting Films,” and helps develop planar quasiparticle tunneling spectroscopy as a vital probe of the energy gap of metallic superconductors.
Charles P. Slichter and his student L.C. Hebel perform the first NMR studies on superconducting aluminum. This is a major feat in itself because superconductors exclude the magnetic fields and radio waves used to perform NMR spectroscopy. The results of their experiments are recognized as the first proof of the electron-pairing concept central to the Bardeen–Cooper–Schrieffer (BCS) theory of superconductivity.
David Pines returns to Illinois as a professor of physics and electrical engineering.
1959William ‘Bill’ L. McMillan begins work with John Bardeen as a doctoral student.
1960David Pines publishes “The Many Body Problem,” a collection of the pioneering early papers on many body theory and quantum liquids.
1961Peter Mansfield becomes a postdoctoral researcher under Charles P. Slichter with the intent of using NMR to study doped metals. During his two years at Illinois, he and Slichter attempt to get a clean NMR signal from a superconductor full of impurities but are unable to do so. After leaving Illinois, Mansfield realizes the “failed experiment” actually pointed to a great way to detect impurities, the principle of MRI. In his 2003 Nobel Prize biography, Mansfield notes, “the experience that I gained on this project and the knowledge and background that I learnt during my stay in Illinois were invaluable.”
1962Anthony J. Leggett joins David Pines’ research group as a postdoctoral research associate to work on Fermi-liquid effects in the superfluid phase, where he becomes interested in the (at the time hypothetical) superfluid phase of liquid 3He. The year spent at Illinois would be a turning point in Leggett’s academic career.
William L. McMillan receives his doctorate. His thesis on the ground state of liquid helium and its superfluidity mark the first application of Monte Carlo methods to a quantum system. In the same year, McMillan becomes a postdoc at Bell Labs, where he and John Rowell work on deriving phonon spectra in superconductors from electron tunneling data and publish a series of papers on their research.
1964Brian Josephson joins the Department of Physics as John Bardeen and David Pines’ postdoctoral research associate to study superconductivity. He would later be nominated by Bardeen for the Nobel Prize in Physics, received in 1973 “for his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effects.”
Dillon E. Mapother measures the superconducting critical field curves for pure Sn, In, and Hg down to about 0.3 K, providing a sensitive test for details of the BCS theory.
David Pines and Philippe Nozières publish The Theory Of Quantum Liquids. It is originally two separate volumes, with Volume I covering “normal” Fermi liquids, such as 3He and electrons in metals. Volume II consists of a detailed treatment of Bose condensation and liquid 4He, including the development of a Bose liquid theory and a microscopic basis for the two-fluid model.
Ansel C. Anderson and John Wheatley, with graduate student William Abel, measure the propagation of zero sound in liquid 3He at 2 mdeg on the magnetic temperature scale, confirming the theoretical prediction by Lev Landau in 1957.
1966Charles P. Slichter is elected to the National Academy of Sciences.
1967J. Robert Schrieffer is awarded the Oliver E. Buckley Condensed Matter Physics Prize of the American Physical Society “for his contributions to many-body theory and its application to the interpretation of experiments, especially in the field of superconductivity.”
1968David Pines, with collaborators Gordon Baym and Chris Pethick, begins studying superfluidity in neutron stars, in particular, the mysterious, sudden observed increases in the rotational speed of pulsars, termed “glitches.” Their groundbreaking work is published in Nature.
1969The Nobel Prize in Physics 1972 is awarded jointly to John Bardeen, Leon Cooper, and J. Robert Schrieffer “for their jointly developed theory of superconductivity, usually called the BCS-theory.”
William L. McMillan returns to Illinois as a professor of physics. Before leaving Bell Labs, he becomes intrigued by liquid crystals and begins using a Landau-type theory to analyze the various phase transitions. He carries out experiments to confirm predictions of the theory.
Anthony J. Leggett, while a faculty member at the University of Sussex, spends the next year on what would be his Nobel Prize-winning research: identifying the microscopic mechanism underlying superfluidity in 3He. Leggett recognizes that it is fundamentally different from the forms of superfluidity observed to that point and uses theoretical techniques previously developed for superconductivity.
1972David Pines is elected to the National Academy of Sciences.
1973Ansel C. Anderson, with his graduate student Gregory Sellers and colleague Howard Birnbaum, measure the specific heat of superconducting Nb and Ta in the temperature range 0.06–2 K and find no evidence suggestive of a second superconducting energy gap.
1974John C. Wheatley is elected to the National Academy of Sciences.
1975William L. McMillan publishes the theory of discommensurations and the commensurate-incommensurate charge-density-wave phase transition, an outgrowth of his work on liquid crystals. This theory is basic to much of the subsequent work in the field.
1976Donald M. Ginsberg and his research group contribute to the understanding of the effects of magnetic and non-magnetic impurities on the electronic structure of superconductors through a wide variety of measurements, including electronic transport, thermal conductivity, specific heat, and magnetic susceptibility. This research thrust is highly productive, and the group publishes multiple journal articles on the topic through 1983; key contributors to this work include graduate students J.W. Thomasson, J.X. Przybysz, Tom Lemberger, B.C. Gibson, J.-K. Tsang, and B.D. Terris.
1977William L. McMillan receives the 1978 Fritz London Award for his work with John Rowell on phonon spectra in superconductors.
1978Eduardo Fradkin and Stephen H. Shenker discover the proof that when matter fields carry the fundamental unit of charge, the Higgs and confinement phases of gauge theories are smoothly connected to each other and are as different as a liquid is from a gas. This result remains one of the cornerstones of our understanding of the phases of gauge theories and represents a lasting contribution to elementary particle physics.
James Wolfe and G.A. Northrop introduce phonon imaging, which contributes graphically and quantitatively to far-reaching topics in phonon physics. Utilizing tiny superconducting detectors and laser-scanned heat sources, phonon imaging has elucidated diverse physical phenomena—phonon focusing, lattice dynamics, and phonon scattering at interfaces, superlattices, and defects. Wolfe uses this novel imaging technique to study excitonic matter and phonon propagation at ultracold temperatures.
1979Miles V. Klein and R. Sooryakumar use Raman scattering to observe an excitation in superconducting 2H-NbSe2 that is later recognized by Nobel Prize recipient Peter Higgs and others as the first experimental observation of a Higgs mode.
1980Anthony J. Leggett joins Illinois as the John D. and Catherine T. MacArthur Professor.
1982Miles V. Klein and graduate student Steve Dierker develop a theory of Raman scattering in superconductors that generalizes previous calculations based on BCS theory.
William L. McMillan dies after a vehicle accident. At the time of his death, 12 papers are in preparation or submitted; at least 5 are posthumously printed, including his research into the random Ising model.
1984Eduardo Fradkin pioneers the use of Dirac fermions for condensed matter physics problems, particularly in two space dimensions. His work on Dirac fermions on random fields is now regarded as the universality class of the transition between quantum Hall plateaus in the integer Hall effect. This work is important for the description of quasiparticles in disordered d-wave superconductors and in the recently discovered topological insulator materials.
1986Donald M. Ginsberg extends his research to incorporate binary and ternary compounds, finally focusing on the molybdenum chalcogenides (sometimes referred to as Chevrel compounds), perhaps the most complex superconducting materials known at the time. Key contributions to determining the structure and physical properties of the Chevrels are made by Ginsberg and graduate students Donald J. Holmgren, Brian G. Pazol, and William H. Wright, in research spanning 1986 to 1988. Because of the complexity and inherent sensitivity and instability of these Chevrel compounds, Ginsberg realizes the necessity of growing his own well-characterized and clean crystals to measure their fundamental properties. He becomes a world leader in preparing samples of these compounds and supplies crystals to dozens of colleagues for a broad variety of measurements.
1987Miles V. Klein and graduate student S. Lance Cooper use Raman scattering to uncover some of the first evidence for a highly anisotropic and unconventional superconducting gap in the high-temperature superconductor YBCO, using crystals grown by Donald M. Ginsberg and his students Brian Pazol and Joseph P. Rice.
1988Charles P. Slichter’s group uses 89Y NMR to measure the internal magnetic field of a sample of YBa2Cu307–δ (Tc = 90 K) in the superconducting state to correct for the effects of the Meissner shielding currents. Their results are consistent with conventional BCS s-wave pairing, but the authors cannot rule out d-wave pairing.
The Science and Technology Center for Superconductivity is established at Illinois (funded by the National Science Foundation) to study the materials, the phenomenon, and possible applications of high-temperature superconductivity. The grant is written by Miles V. Klein, who also spearheads the effort to obtain funds from the Illinois legislature for the building.
David Pines, Alexander Balatsky, and Philippe Monthoux propose the “spin fluctuation theory” as a theoretical framework for high-temperature superconductivity. It is one of two leading theories for the phenomena, the other being the “resonating-valence-bond theory” proposed by Philip W. Anderson in 1987.
1991Charles P. Slichter’s group discovers that the electrons in YBCO exhibit a BCS spin-singlet, orbital-d-wave pairing state. This work is one of the first indications that conventional BCS pairing does not hold for the cuprates.
1992Dale Van Harlingen, Donald M. Ginsberg, Anthony J. Leggett, and graduate student David Wollman pioneer the phase-sensitive SQUID interferometry technique for determining the symmetry of the superconducting order parameter of YBCO and verify the exotic d-wave symmetry, a discovery that would launch a still-ongoing effort to understand the symmetry and mechanism of unconventional superconductors.
Charles P. Slichter shares the Comstock Prize in Physics of the National Academy of Sciences with his former graduate student L. Charles Hebel “for his seminal contributions to the development and application of magnetic resonance in condensed matter, including the first experimental proof of pairing correlations in superconductors and fundamental studies in surface science and catalysis.”
Peter Mansfield is knighted by Queen Elizabeth II “for services to physics.”
1993Anthony J. Leggett is awarded the John Bardeen Prize “for the development of the pairing theory to account for the thermodynamic and dynamic properties of strong coupling superconductors.” He shares the prize with G.M. Eliashberg.
1994Charles P. Slichter, with colleagues at Argonne National Laboratory, measures 13C NMR spin-lattice relaxation rates 1/T1 and Knight shifts Ks in the quasi-two-dimensional organic superconductor κ–(ET)2Cu[N(CN)2]Br (Tc = 11.6 K), which provide evidence against the BCS electron-phonon mechanism as the source of the superconductivity.
1995Charles P. Slichter is awarded the Oliver E. Buckley Condensed Matter Physics Prize of the American Physical Society “for his original and creative applications of the magnetic resonance techniques to elucidate the microscopic properties of condensed matter systems including, especially, superconductors.”
1996In research published in Science, Miles V. Klein, postdoc Girsh Blumberg, and graduate student Moonsoo Kang find evidence in a cuprate superconductor for a partially coherent state, formed from incoherent quasiparticles, that evolves with decreasing temperature to create the global superconducting state below Tc.
Anthony J. Leggett is elected to the National Academy of Sciences as a foreign member.
Donald M. Ginsberg celebrates his retirement with a day-long symposium entitled “Superconductivity with a Smile” (April 19, 1997). By this point in his career, Ginsberg had published more than 240 papers, authored several influential review articles and book chapters, and authored the section on superconductivity in the Encyclopedia Britannica.
Laura H. Greene and her students observe spontaneous surface-induced broken time-reversal symmetry in YBCO and a change in sign of the superconducting order parameter on the Fermi surface, revealing the presence of an Andreev bound state indicative of an unconventional d-wave order parameter.
Laura H. Greene receives the U.S. Department of Energy’s E.O. Lawrence Award “for her research in novel materials, including her pioneering experiments on tunneling and proximity effects in superconductors, and for elucidating the origin of fundamental surface effects in high-temperature superconductors, including the zero-bias conductance anomaly in high-temperature superconductors.”
Donald M. Ginsberg and Dale Van Harlingen are awarded the Oliver E. Buckley Prize in Condensed Matter Physics of the American Physical Society “for using phase-sensitive experiments in the elucidation of the orbital symmetry of the pairing function in high-Tc superconductors.” They share the award with Chang C. Tsuei and John Robert Kirtley, both of the IBM T.J. Watson Research Center.
Eduardo Fradkin, along with Steven A. Kivelson and Victor J. Emery, introduce the notion of electronic liquid crystal states, which are phases of quantum fermionic strongly correlated systems exhibiting properties akin to those of classical complex fluids. These ideas play a crucial role in the current understanding of the pseudogap regime of high-temperature superconductors.
1998Miles V. Klein, S. Lance Cooper, and colleagues discover electron scattering below the 2Δ gap in nonmagnetic borocarbide superconductors, which challenges the conventional view that the borocarbides are BCS-type superconductors.
Russell Giannetta and postdoc Ruslan Prozorov, along with colleagues at the University of Maryland, use penetration-depth measurements to show evidence for nodal quasiparticles in electron-doped cuprates. Lower temperatures and higher resolution combine to permit a more precise determination of the temperature dependence of λ(T) than any previously reported.
2000Philip W. Phillips and Dennis Dalidovich demonstrate theoretically that bosons can exist in a metallic state, which disrupts the transition from a superconductor to an insulator in thin-film superconductors. Phillips coins the term Bose metals to describe this class of materials.
2002Anthony J. Leggett shares the 2003 Nobel Prize in Physics with Alexei Abrikosov and Vitaly Ginzburg “for pioneering contributions to the theory of superconductors and superfluids.”
Peter Mansfield and Paul Lauterbur share the 2003 Nobel Prize in Physiology or Medicine “for their discoveries concerning magnetic resonance imaging.”
Dale Van Harlingen is elected to the National Academy of Sciences.
2003Anthony J. Leggett is knighted by Queen Elizabeth II. He is appointed Knight Commander of the Order of the British Empire “for services to physics.”
2004A team of researchers, led by Alexey Bezryadin and Paul Goldbart and including their graduate students David Hopkins and David Pekker, use strands of DNA as tiny scaffolds to create superconducting nanodevices that demonstrate a new type of quantum interference phenomenon. These nanowire quantum interference devices (NQIDs) consist of superconducting wires having diameters as small as 5 nm to 15 nm, and they have potential applications in measuring magnetic fields and mapping the phase of superconductivity. The research opens new possibilities for using DNA-based scaffolds in nanoscale electronic devices.
Peter Abbamonte, who received a Ph.D. from Illinois Physics in 1999, is recruited back to the University of Illinois as faculty. He brings with him his pioneering technique of resonant soft x-ray scattering, which he developed as a postdoc at the University of Groningen in The Netherlands. He and his group would continue to refine the technique, now in use at every major synchrotron facility in the world. The Abbamonte group has published more than 20 papers using the technique.
2005Laura H. Greene and David M. Ceperley are elected to the National Academy of Sciences.
2006Charles P. Slichter receives the National Medal of Science from President George W. Bush for, among other achievements, his pioneering work in elucidating the mechanisms of both conventional (BCS) and high-temperature superconductors.
Eduardo Fradkin and a group of researchers clarify the notion and significance of “intertwined orders” in the context of cuprate high-temperature superconductors and more generally in strongly correlated systems. This concept would lead to the formulation of a new superconducting state known as a pair density wave in which charge, spin, and superconducting orders are closely intertwined with each other. This state is the main competitor of the uniform d-wave superconductor. It has been found to exist in a wide range of classes of materials from the cuprates to the heavy fermions and kagome superconductors.
To commemorate the 50th anniversary of the Bardeen–Cooper–Schrieffer theory of superconductivity (BCS), the Department of Physics at Illinois hosts BCS@50, a four-day conference dedicated to the history, impact, and contemporary research directions enabled by BCS. Renowned physicists from around the globe attend. Each day’s invited talks are themed on different aspects of superconductivity. Day 1 covers the history and people behind BCS; day 2, contemporary trends in research; day 3, the technological impact of BCS; and day 4, the impact of BCS on other subdisciplines of physics. As part of the celebration, the public is invited to a lecture on the quantum magic of superconductivity.
View the 2007 event program →
Miles V. Klein and collaborators at Bell Laboratories and ETH Zürich discover the Leggett collective mode in a multiband MgB2 superconductor.
Laura H. Greene and her collaborators at Los Alamos National Laboratory show the first spectroscopic evidence for d-wave order-parameter symmetry and Andreev reflection in the heavy-fermion superconductor CeCoIn5.
The U.S. Department of Energy Office of Science invests millions of dollars into the Center for Emergent Superconductivity (CES), an Energy Frontier Research Center. The CES is a a collaboration between Illinois, Brookhaven National Laboratory, and Argonne National Laboratory. The Illinois effort is led by Laura H. Greene.
David Pines is awarded the John Bardeen Prize “for phonon-mediated pairing of electrons in conventional superconductors and superfluidity in nuclear matter.”
2009Nigel Goldenfeld is elected to the National Academy of Sciences.
2010University of Illinois physicists, led by experimentalist Raffi Budakian and theorist Paul Goldbart, report the first observation of half quantum vortices (HQVs) in strontium ruthenium oxide (SRO), an unconventional superconductor. Using state-of-the-art nanofabrication methods and exquisitely sensitive cantilever-based magnetometry techniques developed by the group, the researchers observe minute fluctuations in the magnetism of tiny rings of SRO. HQVs are an exotic state of matter predicted theoretically for more than 30 years but never before directly observed. These HQVs in SRO may provide the basis for topological quantum computing.
Nadya Mason leads a team, including theorists Taylor Hughes and Paul Goldbart, that isolates unique bound states involving electrons and holes—Andreev bound states—that form in graphene-superconductor junctions and enable transport of supercurrents through non-superconducting materials. The research is published in Nature Physics.
Robert G. Leigh and Philip W. Phillips, along with their team at Illinois, find a unique way to model the behavior of interacting electrons in unconventional superconductors by using a model of charged black holes. Their approach marks a significant step in resolving the physics of Mott insulators, which is crucial to understanding superconductivity in these materials.
A team led by experimentalist Nadya Mason and theorist Paul Goldbart discovers a two-dimensional superconducting system that systematically approaches a zero-temperature metallic state, confirming so-called Anderson localization, a prediction made by Philip W. Anderson in 1958. By creating nanometer-scale arrays of physically separated superconducting “islands” on normal metal films, the group is able to show the temperature-dependent transition to the superconducting state is a function of the island separation. This research is published in Nature Physics in 2012.
Calculations by David M. Ceperley and J.M. McMahon predict a pressure-dependent increase in the high-temperature superconducting transition temperature over the pressure range 500 GPa to 3.5 TPa in atomic metallic hydrogen.
2011Physicists from Illinois and Purdue University employ fractal geometry to investigate superconductors. They observe that nanoscale electron lines on the surface of high-temperature superconductors actually originate deep within the material. The study aims to deepen the understanding of how superconductors can conduct electricity without resistance and potentially pave the way for room-temperature superconductors.
James N. Eckstein is awarded the 2012 Bernd T. Matthias Prize, a triennial award that recognizes innovative contributions to the material aspects of superconductivity. Eckstein is cited for his “pioneering and sustained contributions to the novel synthesis and engineering of superconducting materials.” He shares the 2012 Prize with colleagues Ivan Bozovic and Dirk Johrendt.
2012Eduardo Fradkin is elected to the National Academy of Sciences.
2013An international team of scientists makes the first experimental observation of the quantum critical point (QCP) in the unconventional superconductor TiSe2. This finding has important implications for the understanding of superconducting behavior and may contribute to the development of better superconducting materials, potentially even room-temperature superconductors.
2014
Researchers at Illinois develop an algorithm that reverses the typical approach of condensed matter physics. Instead of starting with a Hamiltonian and solving for wave functions, their algorithm begins with a desired set of properties and generates Hamiltonians that produce those properties. This approach streamlines the search for interesting physics, potentially benefiting the study of phenomena such as superconductivity. The algorithm allows researchers to find Hamiltonians for previously unexplained wave functions and could guide experimentalists in discovering new physics.
2018In collaboration with the SLAC National Accelerator Laboratory, researchers at Illinois use a novel x-ray scattering technique to probe the charge order phase in a copper-oxide superconductor and find that charge order fluctuations are closely related to the material’s superconducting critical temperature. The study reveals that the formation of charge-order patterns follows a universal scaling law.
2019A team of Illinois researchers led by Vidya Madhaven, in collaboration with researchers from the National Institute of Standards and Technology, the University of Maryland, Boston College, and ETH Zürich, uses high-resolution microscopy tools to peer at the inner workings of an unusual type of superconductor, uranium ditelluride (UTe2). Their measurements reveal strong evidence that this material may be a natural home to an exotic quasiparticle that’s been hiding from physicists since it was first theorized in 1937: the Majorana particle.
Peter Abbamonte and Vidya Madhavan are two of twenty US scientists named as investigators in the Gordon and Betty Moore Foundation’s Emergent Phenomena in Quantum Systems Initiative (EPiQS). EPiQS prioritizes high-risk, high-reward fundamental research programs in quantum materials to foster scientific breakthroughs. Abbamonte will use the award to develop new spectroscopy instrumentation capable of measuring for the first time the interactions of quantum particles. Abbamonte’s new investigative tool, called “coincidence M-EELS,” will provide a more complete understanding of the mechanics underlying superconductivity in a class of materials known as strange metals.” Madhavan will use part of her grant to develop new instrumentation that will enable her group to measure dynamic changes in the superconducting order parameter in greater detail than is possible today.
Philip W. Phillips, along with Luke Yeo and Edwin W. Huang,makes a significant breakthrough in understanding copper-oxide high-temperature superconductors, also known as cuprates. The researchers solve a representative model of the cuprate problem, demonstrating the existence of superconductivity in doped Mott insulators and revealing that cuprates operate outside the framework of traditional BCS theory. This groundbreaking work sheds light on the mysterious properties of cuprates and represents a crucial step in the quest to unlock their technological potential.
James N. Eckstein and Tai-Chang Chiang, in collaboration with researchers from The University of Tokyo and international partners, make significant advancements in understanding the physics of coupling topological materials with conventional superconductors. They employ their “flip-chip” method, first developed in 2018, to fabricate bulk insulating topological insulator (TI) films on superconductor (SC) substrates. This allows them to investigate the proximity effect between these materials more precisely. The results indicate that when the TI film is bulk insulating, no superconductivity is observed at the surface, challenging previous claims of strong superconducting order. This research offers valuable insights into the potential for creating topological superconductors, with implications for various technological applications.
2020Nadya Mason is elected to the National Academy of Sciences.
James N. Eckstein is awarded the James C. McGroddy Prize for New Materials of the American Physical Society “for pioneering the atomic-layer-by-layer synthesis of new metastable complex oxide materials, and the discovery of resulting novel phenomena,” which enabled seminal studies of emergent behavior in superconducting and magnetic materials.
2021Philip W. Phillips, Edwin Huang, and Gabriele La Nave uncover a key connection between symmetry and Mott physics (the physics underlying high-temperature superconductors). The team shows that superconductivity in a doped Mott insulator lacks a Hebel-Slichter peak. Previous work tackling Mott physics dealt with strong interactions by focusing on analytically intractable models, such as the Hubbard model.
In a separate project, Philip W. Phillips, Jinchao Zhao, and Gabriele La Nave establish a new fixed point for Mott. The team expands on this work in a second publication, providing proof of a stable fixed point for strongly correlated electron matter.
A team of condensed matter experimentalists and theorists at Illinois discover that variations in patterns of charge density among different cuprates may be manifestations of the same general behavior, and that behavior is possibly universal across the cuprate family.
2022Fahad Mahmood and a team of Illinois researchers detect the existence of a charge density wave (CDW) of electrons that acquires mass as it interacts with the background lattice ions of the material over long distances. Their results are a direct measurement of the Anderson–Higgs mechanism (of mass acquisition) and the first known demonstration of a massive phason in a CDW material, predicted more than 40 years ago.
Vidya Madhavan and a team of Illinois researchers notice unusual waves of charge within a crystal of uranium ditelluride. (UTe2). Theorists on the team develop a model that links the experimental observations to a previously unseen facet of the crystal’s unusual superconductivity.
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This story was published June 13, 2024.