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Title: Discovery of a new type of topological Weyl fermion semimetal state in Mo xW 1-xTe 2

Here, the recent discovery of a Weyl semimetal in TaAs offers the first Weyl fermion observed in nature and dramatically broadens the classification of topological phases. However, in TaAs it has proven challenging to study the rich transport phenomena arising from emergent Weyl fermions. The series Mo xW 1-xTe 2 are inversion-breaking, layered, tunable semimetals already under study as a promising platform for new electronics and recently proposed to host Type II, or strongly Lorentz-violating, Weyl fermions. Here we report the discovery of a Weyl semimetal in Mo xW 1-xTe 2 at x=25%. We use pump-probe angle-resolved photoemission spectroscopy (pump-probe ARPES) to directly observe a topological Fermi arc above the Fermi level, demonstrating a Weyl semimetal. The excellent agreement with calculation suggests that Mo xW 1-xTe 2 is a Type II Weyl semimetal. We also find that certain Weyl points are at the Fermi level, making Mo xW 1-xTe 2 a promising platform for transport and optics experiments on Weyl semimetals.
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  1. Princeton Univ., Princeton, NJ (United States)
  2. Univ. of Tokyo, Chiba (Japan)
  3. Nanjing Univ., Nanjing (China)
  4. Nanyang Technological Univ. (Singapore)
  5. National Univ. of Singapore (Singapore)
  6. National Tsing Hua Univ., Hsinchu (Taiwan)
  7. Univ. of Central Florida, Orlando, FL (United States)
  8. National Tsing Hua Univ., Hsinchu (Taiwan); Academia Sinica, Taipei (Taiwan)
  9. Nanyang Technological Univ. (Singapore); CINTRA CNRS/NTU/THALES (Singapore)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Princeton Univ., NJ (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 36 MATERIALS SCIENCE; electronic properties and materials; topological insulators
OSTI Identifier: