Visualizing Type-II Weyl Points in Tungsten Ditelluride by Quasiparticle Interference

Chun-Liang Lin, Ryuichi Arafune, Ro Ya Liu, Masato Yoshimura, Baojie Feng, Kazuaki Kawahara, Zeyuan Ni, Emi Minamitani, Satoshi Watanabe, Youguo Shi, Maki Kawai, Tai Chang Chiang, Iwao Matsuda, Noriaki Takagi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Weyl semimetals (WSMs) are classified into two types, type I and II, according to the topology of the Weyl point, where the electron and hole pockets touch each other. Tungsten ditelluride (WTe 2 ) has garnered a great deal of attention as a strong candidate to be a type-II WSM. However, the Weyl points for WTe 2 are located above the Fermi level, which has prevented us from identifying the locations and the connection to the Fermi arc surface states by using angle-resolved photoemission spectroscopy. Here, we present experimental proof that WTe 2 is a type-II WSM. We measured energy-dependent quasiparticle interference patterns with a cryogenic scanning tunneling microscope, revealing the position of the Weyl point and its connection with the Fermi arc surface states, in agreement with prior theoretical predictions. Our results provide an answer to this crucial question and stimulate further exploration of the characteristics of WSMs.

Original languageEnglish
Pages (from-to)11459-11465
Number of pages7
JournalACS Nano
Issue number11
StatePublished - 28 Nov 2017


  • Fermi arc
  • quasiparticle interference
  • scanning tunneling microscopy
  • topological matter
  • transition metal dichalcogenides
  • Weyl semimetals
  • WTe


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