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This content will become publicly available on July 11, 2017

Title: Spectroscopic evidence for a type II Weyl semimetallic state in MoTe2

In a type I Dirac or Weyl semimetal, the low-energy states are squeezed to a single point in momentum space when the chemical potential μ is tuned precisely to the Dirac/Weyl point1, 2, 3, 4, 5, 6. Recently, a type II Weyl semimetal was predicted to exist, where the Weyl states connect hole and electron bands, separated by an indirect gap7, 8, 9, 10. This leads to unusual energy states, where hole and electron pockets touch at the Weyl point. Here we present the discovery of a type II topological Weyl semimetal state in pure MoTe2, where two sets of Weyl points (W±2 , W±3) exist at the touching points of electron and hole pockets and are located at different binding energies above EF. Using angle-resolved photoemission spectroscopy, modelling, density functional theory and calculations of Berry curvature, we identify the Weyl points and demonstrate that they are connected by different sets of Fermi arcs for each of the two surface terminations. We also find new surface ‘track states’ that form closed loops and are unique to type II Weyl semimetals. Lastly, this material provides an exciting, new platform to study the properties of Weyl fermions.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [1] ;  [1] ;  [7] ;  [8] ;  [2] ;  [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States)
  2. The Ohio State Univ., Columbus, OH (United States)
  3. Osaka Univ., Osaka (Japan)
  4. Univ. of Tennessee, Knoxville, TN (United States)
  5. RIKEN Center for Emergent Matter Science (CEMS), Saitama (Japan)
  6. RIKEN Center for Emergent Matter Science (CEMS), Saitama (Japan); Tohoku Univ., Miyagi (Japan)
  7. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  8. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
OSTI Identifier:
1278751
Report Number(s):
IS-J--9004
Journal ID: ISSN 1476-1122; nmat4685
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Nature Materials
Additional Journal Information:
Journal Name: Nature Materials; Journal ID: ISSN 1476-1122
Publisher:
Nature Publishing Group
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY