Two-Dimensional Dirac Fermions Protected by Space-Time Inversion Symmetry in Black Phosphorus

Jimin Kim, Seung Su Baik, Sung Won Jung, Yeongsup Sohn, Sae Hee Ryu, Hyoung Joon Choi, Bohm Jung Yang, Keun Su Kim

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

We report the realization of novel symmetry-protected Dirac fermions in a surface-doped two-dimensional (2D) semiconductor, black phosphorus. The widely tunable band gap of black phosphorus by the surface Stark effect is employed to achieve a surprisingly large band inversion up to ∼0.6 eV. High-resolution angle-resolved photoemission spectra directly reveal the pair creation of Dirac points and their movement along the axis of the glide-mirror symmetry. Unlike graphene, the Dirac point of black phosphorus is stable, as protected by space-time inversion symmetry, even in the presence of spin-orbit coupling. Our results establish black phosphorus in the inverted regime as a simple model system of 2D symmetry-protected (topological) Dirac semimetals, offering an unprecedented opportunity for the discovery of 2D Weyl semimetals.

Original languageEnglish
Article number226801
JournalPhysical review letters
Volume119
Issue number22
DOIs
Publication statusPublished - 2017 Nov 29

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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