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.
@article{arxiv.2007.05666,
title = {Observation of inverted band structure in topological Dirac-semimetal candidate CaAuAs},
author = {Kosuke Nakayama and Zhiwei Wang and Daichi Takane and Seigo Souma and Yuya Kubota and Yuki Nakata and Cephise Cacho and Timur K. Kim and Sandy Adhitia Ekahana and Ming Shi and Miho Kitamura and Koji Horiba and Hiroshi Kumigashira and Takashi Takahashi and Yoichi Ando and Takafumi Sato},
journal= {arXiv preprint arXiv:2007.05666},
year = {2020}
}