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arXiv · 1703.07488

Elemental topological Dirac semimetal: α-Sn on InSb(111)

Cai-Zhi Xu·Yang-Hao Chan·Yige Chen·Peng Chen·Xiaoxiong Wang·Catherine Dejoie·Man-Hong Wong·Joseph Andrew Hlevyack·Hyejin Ryu·Hae-Young Kee·Nobumichi Tamura·Mei-Yin Chou·Zahid Hussain·Sung-Kwan Mo·Tai-Chang Chiang
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Abstract

Three-dimensional (3D) topological Dirac semimetals (TDSs) are rare but important as a versatile platform for exploring exotic electronic properties and topological phase transitions. A quintessential feature of TDSs is 3D Dirac fermions associated with bulk electronic states near the Fermi level. Using angle-resolved photoemission spectroscopy (ARPES), we have observed such bulk Dirac cones in epitaxially-grown α-Sn films on InSb(111), the first such TDS system realized in an elemental form. First-principles calculations confirm that epitaxial strain is key to the formation of the TDS phase. A phase diagram is established that connects the 3D TDS phase through a singular point of a zero-gap semimetal phase to a topological insulator (TI) phase. The nature of the Dirac cone crosses over from 3D to 2D as the film thickness is reduced.

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Cai-Zhi Xu, Yang-Hao Chan, Yige Chen, Peng Chen, Xiaoxiong Wang, Catherine Dejoie, Man-Hong Wong, Joseph Andrew Hlevyack, Hyejin Ryu, Hae-Young Kee, Nobumichi Tamura, Mei-Yin Chou, Zahid Hussain, Sung-Kwan Mo, Tai-Chang Chiang. 2017-03-22. Elemental topological Dirac semimetal: α-Sn on InSb(111). https://doi.org/10.1103/physrevlett.118.146402

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