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| Dirac semimetals | |
|---|---|
| Name | Dirac semimetals |
| Type | Material class |
| Discovered | 2010s |
| Notable | Cd3As2, Na3Bi, ZrTe5 |
| Fields | Condensed matter physics, Materials science, Quantum materials |
Dirac semimetals are a class of quantum materials characterized by linear band crossings at discrete points in momentum space that host fourfold-degenerate quasiparticles. They bridge concepts from relativistic quantum field theory and solid-state physics and have been investigated across experimental platforms by groups at institutions such as Massachusetts Institute of Technology, Stanford University, Max Planck Society, Harvard University, and Oak Ridge National Laboratory. Research on these materials intersects with work by award-winning physicists associated with Nobel Prize in Physics laureates and major collaborative efforts at facilities like Argonne National Laboratory and European Synchrotron Radiation Facility.
Dirac semimetals emerged in the wake of theoretical predictions and experimental verification similar to milestones achieved for graphene, topological insulators, and Weyl semimetals. Early experimental reports focused on materials such as Cd3As2 and Na3Bi, with contributions from research teams at University of California, Berkeley, Chinese Academy of Sciences, and Peking University. The field subsequently linked to broader initiatives at centers like Bell Labs, IBM Research, and the National Institute of Standards and Technology aiming to exploit relativistic quasiparticles for novel device concepts and fundamental tests paralleling historical programs at CERN and Bell Telephone Laboratories.
The electronic structure of these compounds features fourfold-degenerate band crossings known as Dirac points, conceptually related to solutions of the Dirac equation studied in the context of Paul Dirac's work and used in analyses similar to those of Haldane model and Kane-Mele model. Band topology analysis often references techniques developed at Princeton University, University of Cambridge, and Institute for Quantum Information and Matter. Calculations employ methods pioneered in computational projects at Lawrence Berkeley National Laboratory and software influenced by collaborations with Los Alamos National Laboratory and Oak Ridge National Laboratory.
Stability of Dirac points requires protecting symmetries such as inversion and time-reversal, a theme appearing in symmetry classifications used by groups at Perimeter Institute, Institute for Advanced Study, and Flatiron Institute. Crystalline symmetries like rotational and nonsymmorphic operations studied in works from ETH Zurich, University of Tokyo, and École Normale Supérieure play key roles. Topological invariants and band representations connect to theoretical frameworks developed at California Institute of Technology, Rutgers University, and University of Illinois Urbana-Champaign.
Prototype materials include Cd3As2, Na3Bi, and layered compounds related to ZrTe5 and transition-metal pnictides studied at Columbia University, University of Oxford, and University of Michigan. Synthetic approaches draw on techniques from research groups at Stanford Synchrotron Radiation Lightsource, Brookhaven National Laboratory, and SPring-8, while thin-film and heterostructure realizations leverage capabilities at Georgia Institute of Technology and Korea Advanced Institute of Science and Technology. Studies of related phases reference work on TaAs, NbAs, and other chalcogenides pursued at Max Planck Institute for Chemical Physics of Solids.
Key experimental signatures include high-mobility transport, linear magnetoresistance, nontrivial Berry curvature effects, and characteristic responses in angle-resolved photoemission spectroscopy experiments performed at facilities like Diamond Light Source, National Synchrotron Light Source II, and Swiss Light Source. Quantum oscillation studies performed at High Magnetic Field Laboratory (Grenoble), National High Magnetic Field Laboratory, and Los Alamos National Laboratory complement scanning tunneling microscopy measurements executed at IBM Research–Zurich and University of California, San Diego. Collaborations with cryogenic and high-pressure programs at Max Planck Institute for Solid State Research and Argonne National Laboratory have further elucidated phase behavior.
Theoretical descriptions use effective Hamiltonians akin to the Dirac equation adapted to crystal lattices, tight-binding models rooted in techniques from Linear Muffin-Tin Orbital method developments associated with Cornell University and Daresbury Laboratory, and first-principles density functional theory calculations refined by groups at Toyota Research Institute and Vanderbilt University. Field-theoretic techniques leveraging renormalization group methods developed at Institute for Advanced Study and numerical many-body methods from Simons Foundation supported centers are routinely applied. Cross-disciplinary input traces to seminal work at Los Alamos National Laboratory, Princeton University, and Yale University.
Potential applications encompass high-speed electronics inspired by graphene technologies, spintronics concepts related to research at Hitachi, NEC Corporation, and Intel Corporation, and quantum sensors leveraging properties explored at National Institute of Standards and Technology and Sandia National Laboratories. Proposed devices span photodetectors, terahertz emitters, and topological transistors drawing on collaborative programs at Sony Corporation, Samsung Electronics, and Microsoft Research. Fundamental tests of relativistic quantum effects in solids echo experimental traditions at CERN and precision measurement efforts at National Metrology Institutes.
Category:Quantum materials