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Dirac semimetal in ?-CuI without surface Fermi arcs.

ABSTRACT: Anomalous surface states with Fermi arcs are commonly considered to be a fingerprint of Dirac semimetals (DSMs). In contrast to Weyl semimetals, however, Fermi arcs of DSMs are not topologically protected. Using first-principles calculations, we predict that ?-cuprous iodide (?-CuI) is a peculiar DSM whose surface states form closed Fermi pockets instead of Fermi arcs. In such a fermiological Dirac semimetal, the deformation mechanism from Fermi arcs to Fermi pockets stems from a large cubic term preserving all crystal symmetries and from the small energy difference between the surface and bulk Dirac points. The cubic term in ?-CuI, usually negligible in prototypical DSMs, becomes relevant because of the particular crystal structure. As such, we establish a concrete material example manifesting the lack of topological protection for surface Fermi arcs in DSMs.

SUBMITTER: Le C

PROVIDER: S-EPMC6099897 | biostudies-other | 2018 Aug

REPOSITORIES: biostudies-other

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Dirac semimetal in <i>β</i>-CuI without surface Fermi arcs.

Le Congcong C Wu Xianxin X Qin Shengshan S Li Yinxiang Y Thomale Ronny R Zhang Fu-Chun FC Hu Jiangping J

Proceedings of the National Academy of Sciences of the United States of America 20180730 33

Anomalous surface states with Fermi arcs are commonly considered to be a fingerprint of Dirac semimetals (DSMs). In contrast to Weyl semimetals, however, Fermi arcs of DSMs are not topologically protected. Using first-principles calculations, we predict that β-cuprous iodide (β-CuI) is a peculiar DSM whose surface states form closed Fermi pockets instead of Fermi arcs. In such a fermiological Dirac semimetal, the deformation mechanism from Fermi arcs to Fermi pockets stems from a large cubic ter ...[more]

PMID: 30061416

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