Signatures of Sixfold Degenerate Exotic Fermions in a Superconducting Metal PdSb2. Issue 11 (9th February 2020)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: Advanced materials. Volume 32:Issue 11(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-02-09
• Subjects: angle‐resolved photoemission spectroscopy -- electronic structure -- first principle calculations -- multifold degenerate points -- topological materials; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201906046
• Languages: English
• ISSNs: 0935-9648

Abstract

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 PdSb2 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. Abstract : Condensed matter systems provide immense opportunity to study novel excitations which are otherwise not yet identified as independent particles. Nonmagnetic PdSb2 with pyrite‐type structure contains all the required symmetries to exhibit sixfold degenerate points. Angle‐resolved photoemission spectroscopy measurements along with first‐principles calculations provide signatures of such sextuple points below the Fermi energy in PdSb2 .