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Title: Electronic structure of monolayer 1T'-MoTe 2 grown by molecular beam epitaxy

Monolayer transition metal dichalcogenides (TMDCs) in the 1T' structural phase have drawn a great deal of attention due to the prediction of quantum spin Hall insulator states. The band inversion and the concomitant changes in the band topology induced by the structural distortion from 1T to 1T' phases are well established. However, the bandgap opening due to the strong spin-orbit coupling (SOC) is only verified for 1T'-WTe 2 recently and still debated for other TMDCs. Here we report a successful growth of high-quality monolayer 1T'-MoTe 2 on a bilayer graphene substrate through molecular beam epitaxy. Using in situ angle-resolved photoemission spectroscopy (ARPES), we have investigated the low-energy electronic structure and Fermi surface topology. The SOC-induced breaking of the band degeneracy points between the valence and conduction bands is clearly observed by ARPES. However, the strength of SOC is found to be insufficient to open a bandgap, which makes monolayer 1T'-MoTe 2 on bilayer graphene a semimetal.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ; ORCiD logo [5] ;  [6] ;  [6] ;  [7] ;  [3] ;  [3] ; ORCiD logo [8]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chinese Academy of Sciences, Shanghai (China); Shanghai Tech Univ., Shanghai (China)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); National Univ. of Defense Technology, Changsha (China)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Max Planck-POSTECH/Hsinch Center for Complex Phase Materials, Gyeongbuk (South Korea)
  5. Pusan National Univ., Busan (South Korea)
  6. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  7. Chinese Academy of Sciences, Shanghai (China); Shanghai Tech Univ., Shanghai (China)
  8. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-05CH11231; AC02-76SF00515; FA9550-14-1-0277
Type:
Accepted Manuscript
Journal Name:
APL Materials
Additional Journal Information:
Journal Volume: 6; Journal Issue: 2; Journal ID: ISSN 2166-532X
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (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
OSTI Identifier:
1437578
Alternate Identifier(s):
OSTI ID: 1421017; OSTI ID: 1435115