npj Quantum Materials (Jan 2017)

CaTe: a new topological node-line and Dirac semimetal

  • Yongping Du,
  • Feng Tang,
  • Di Wang,
  • Li Sheng,
  • Er-jun Kan,
  • Chun-Gang Duan,
  • Sergey Y. Savrasov,
  • Xiangang Wan

DOI
https://doi.org/10.1038/s41535-016-0005-4
Journal volume & issue
Vol. 2, no. 1
pp. 1 – 4

Abstract

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Topological physics: a predicted node-line semimetal CaTe Topological insulators are materials with non-trivial topological order that are insulating in their bulk but conductive on their surface. Recent findings extend the topological states to three-dimensional semimetals that host exotic physical phenomena such as Weyl fermion quantum transport and Hall effects. Among the three types of topological semimetals, three-dimensional Dirac semimetals evolve to Weyl analogs upon breaking of time reversal or inversion symmetry. Here, the theoretical work by a team led by Professor Xiangang Wan from Nanjing University in China proposes a new phase that falls into the third category: node-line semimetals. Based on first-principles calculations and effective model analysis, CsCl structured CaTe is predicted to be a node-line semimetals with characteristic drumhead-like surface states if spin-orbit coupling is absent. When spin-orbit coupling is included, CaTe becomes a three-dimensional Dirac semimetal.