Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals

Bradlyn B, Cano J, Wang Z, Vergniory MG, Felser C, Cava RJ, Bernevig BA (2016)

Publication Type: Journal article

Publication year: 2016

Journal

Science American Association for the Advancement of Science

Book Volume: 353

Article Number: aaf5037

Journal Issue: 6299

DOI: 10.1126/science.aaf5037

Abstract

In quantum field theory, we learn that fermions come in three varieties: Majorana, Weyl, and Dirac. Here, we show that in solid-state systems this classification is incomplete, and we find several additional types of crystal symmetry-protected free fermionic excitations. We exhaustively classify linear and quadratic three-, six-, and eight-band crossings stabilized by space group symmetries in solid-state systems with spin-orbit coupling and time-reversal symmetry. Several distinct types of fermions arise, differentiated by their degeneracies at and along high-symmetry points, lines, and surfaces. Some notable consequences of these fermions are the presence of Fermi arcs in non-Weyl systems and the existence of Dirac lines. Ab initio calculations identify a number of materials that realize these exotic fermions close to the Fermi level.

Involved external institutions

Princeton University US United States (USA) (US) Donostia International Physics Center (DIPC) ES Spain (ES) Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids DE Germany (DE)

How to cite

APA:

Bradlyn, B., Cano, J., Wang, Z., Vergniory, M.G., Felser, C., Cava, R.J., & Bernevig, B.A. (2016). Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals. Science, 353(6299). https://doi.org/10.1126/science.aaf5037

MLA:

Bradlyn, Barry, et al. "Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals." Science 353.6299 (2016).

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