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arXiv · 2007.05666

Observation of inverted band structure in topological Dirac-semimetal candidate CaAuAs

Kosuke Nakayama·Zhiwei Wang·Daichi Takane·Seigo Souma·Yuya Kubota·Yuki Nakata·Cephise Cacho·Timur K. Kim·Sandy Adhitia Ekahana·Ming Shi·Miho Kitamura·Koji Horiba·Hiroshi Kumigashira·Takashi Takahashi·Yoichi Ando·Takafumi Sato
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Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy of ternary pnictide CaAuAs which is predicted to be a three-dimensional topological Dirac semimetal (TDS). By accurately determining the bulk-band structure, we have revealed the coexistence of three-dimensional and quasi-two-dimensional Fermi surfaces with dominant hole carriers. The band structure around the Brillouin-zone center is characterized by an energy overlap between hole and electron pockets, in excellent agreement with first-principles band-structure calculations. This indicates the occurrence of bulk-band inversion, supporting the TDS state in CaAuAs. Because of the high tunability in the chemical composition besides the TDS nature, CaAuAs provides a precious opportunity for investigating the quantum phase transition from TDS to other exotic topological phases.

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Kosuke Nakayama, Zhiwei Wang, Daichi Takane, Seigo Souma, Yuya Kubota, Yuki Nakata, Cephise Cacho, Timur K. Kim, Sandy Adhitia Ekahana, Ming Shi, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Takashi Takahashi, Yoichi Ando, Takafumi Sato. 2020-07-11. Observation of inverted band structure in topological Dirac-semimetal candidate CaAuAs. https://doi.org/10.1103/physrevb.102.041104

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