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Signatures of Sixfold Degenerate Exotic Fermions in a Superconducting Metal PdSb 2
Author(s) -
Kumar Nitesh,
Yao Mengyu,
Nayak Jayita,
Vergniory Maia G.,
Bannies Jörn,
Wang Zhijun,
Schröter Niels B. M.,
Strocov Vladimir N.,
Müchler Lukas,
Shi Wujun,
Rienks Emile D. L.,
Mañes J. L.,
Shekhar Chandra,
Parkin Stuart S. P.,
Fink Jörg,
Fecher Gerhard H.,
Sun Yan,
Bernevig B. Andrei,
Felser Claudia
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201906046
Subject(s) - degenerate energy levels , brillouin zone , fermion , condensed matter physics , dirac fermion , photoemission spectroscopy , superconductivity , metal , physics , materials science , dirac (video compression format) , quantum mechanics , spectral line , neutrino , metallurgy
Abstract Multifold degenerate points in the electronic structure of metals lead to exotic behaviors. These range from twofold and fourfold degenerate Weyl and Dirac points, respectively, to sixfold and eightfold degenerate points that are predicted to give rise, under modest magnetic fields or strain, to topological semimetallic behaviors. The present study shows that the nonsymmorphic compound PdSb 2 hosts six‐component fermions or sextuplets. Using angle‐resolved photoemission spectroscopy, crossing points formed by three twofold degenerate parabolic bands are directly observed at the corner of the Brillouin zone. The group theory analysis proves that under weak spin–orbit interaction, a band inversion occurs.