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Title: Phonon-induced topological transition to a type-II Weyl semimetal

Given the importance of crystal symmetry for the emergence of topological quantum states, we have studied here, as exemplified in NbNiTe 2, the interplay of crystal symmetry, atomic displacements (lattice vibration), band degeneracy, and band topology. For the NbNiTe 2 structure in space-group 53 (Pmna)$-$ having an inversion center arising from two glide planes and one mirror plane with a two-fold rotation and screw axis$-$a full gap opening exists between two band manifolds near the Fermi energy. Upon atomic displacements by optical phonons, the symmetry lowers to space-group 28 (Pma2), eliminating one glide plane along c, the associated rotation and screw axis, and the inversion center. As a result, 20 Weyl points emerge, including four type-IIWeyl points in the Γ-X direction at the boundary between a pair of adjacent electron and hole bands. Thus, optical phonons may offer control of the transition to a Weyl fermion state.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [2] ;  [2] ;  [4]
  1. Ames Lab., Ames, IA (United States)
  2. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  3. Federal Inst. of Technology, Zurich (Switzerland). Theoretical Physics and Station Q Zurich
  4. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Iowa State Univ., Ames, IA (United States). Dept. of Materials Science and Engineering
Publication Date:
Report Number(s):
IS-J-9230
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1702601
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 16; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1355401
Alternate Identifier(s):
OSTI ID: 1351125