Dirac semimetal phase and switching of band inversion in XMg2Bi2 (X = Ba and Sr)

Daichi Takane, Yuya Kubota, Kosuke Nakayama, Tappei Kawakami, Kunihiko Yamauchi, Seigo Souma, Takemi Kato, Katsuaki Sugawara, Shin ichiro Ideta, Kiyohisa Tanaka, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Tamio Oguchi, Takashi Takahashi, Kouji Segawa, Takafumi Sato

Research output: Contribution to journalArticlepeer-review

Abstract

Topological Dirac semimetals (TDSs) offer an excellent opportunity to realize outstanding physical properties distinct from those of topological insulators. Since TDSs verified so far have their own problems such as high reactivity in the atmosphere and difficulty in controlling topological phases via chemical substitution, it is highly desirable to find a new material platform of TDSs. By angle-resolved photoemission spectroscopy combined with first-principles band-structure calculations, we show that ternary compound BaMg2Bi2 is a TDS with a simple Dirac-band crossing around the Brillouin-zone center protected by the C3 symmetry of crystal. We also found that isostructural SrMg2Bi2 is an ordinary insulator characterized by the absence of band inversion due to the reduction of spin–orbit coupling. Thus, XMg2Bi2 (X = Sr, Ba, etc.) serves as a useful platform to study the interplay among crystal symmetry, spin–orbit coupling, and topological phase transition around the TDS phase.

Original languageEnglish
Article number21937
JournalScientific reports
Volume11
Issue number1
DOIs
Publication statusPublished - 2021 Dec

ASJC Scopus subject areas

  • General

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