Type-II Dirac surface states in topological crystalline insulators

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Ching-Kai Chiu
  • Y.-H. Chan
  • Xiao Li
  • Y. Nohara
  • A. P. Schnyder

Detail(s)

Original languageEnglish
Article number035151
Journal / PublicationPhysical Review B
Volume95
Issue number3
Publication statusPublished - 15 Jan 2017
Externally publishedYes

Abstract

Recently, it has been realized that topological Weyl semimetals come in two different varieties: (i) with standard Weyl cones with pointlike Fermi surfaces (type I) and (ii) with tilted Weyl cones that appear at the contact of electron and hole pockets (type II). These two types of Weyl semimetals have very different physical properties, in particular, in their thermodynamics and magnetotransport. Here, we show that Dirac cone surface states of topological crystalline insulators can be distinguished in a similar way. We demonstrate this in terms of a general surface theory and then apply this knowledge to a family of antiperovskites of the form A3EO, where A denotes an alkaline earth metal, while E stands for Pb or Sn. Using ab initio DFT calculations, we investigate the bulk and surface topology of these antiperovskites and show that they exhibit type-I as well as type-II Dirac surface states protected by reflection symmetry. We find that the type-II Dirac states, as opposed to the type-I Dirac states, exhibit characteristic van Hove singularities in their dispersion, which lead to different thermodynamic properties, and which can serve as an experimental fingerprint of type-II surface states. The different magnetotransport characteristics between type-I and type-II surface states are discussed. In addition, we show that both type-I and type-II surface states exhibit an unusual helical spin polarization, which could lead to topological surface superconductivity.

Citation Format(s)

Type-II Dirac surface states in topological crystalline insulators. / Chiu, Ching-Kai; Chan, Y.-H.; Li, Xiao; Nohara, Y.; Schnyder, A. P.

In: Physical Review B, Vol. 95, No. 3, 035151, 15.01.2017.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review