Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals.
Science
; 353(6299): aaf5037, 2016 Aug 05.
Article
em En
| MEDLINE
| ID: mdl-27445310
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article