Band structure study of elemental topological material α-Sn on InSb(111)B

ORAL

Abstract

Research efforts on studying the band structure of elemental topological α-Sn have increased substantially in recent years. Bulk α-Sn is a zero-gap material with an inherent band inversion due to spin-orbit coupling. Interestingly, theoretical calculation proposed strained-induced topological phase transitions from topological Dirac semimetal (TDS) to topological insulator (TI) in α-Sn thin films. Among them, compressively strained α-Sn thin films on InSb(111)B were experimentally claimed to be a 3D TDS for 30-bilayer (BL) film by angle-resolved photoemission spectroscopy (ARPES).1 In this work, α-Sn thin films were grown on InSb(111)B by molecular beam epitaxy (MBE) with epi-InSb as the starting surfaces prepared in the same MBE chamber. Single-crystal α-Sn thin films with excellent crystallinity and smooth surface morphology were characterized by X-ray diffraction and atomic force microscopy; their band structures were studied by ARPES. Much clearer band dispersions were observed for our 30-BL film compared to those in the literature, with virtually no kz dependence over a wide photon energy range from 18 eV to 52 eV for the claimed 3D Dirac state. Our results, therefore, do not support the 3D TDS phase observed in the previous work.1
1C. Z. Xu, et al., PRL 118, 146402 (2017).

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Presenters

  • Keng-Yung Lin

    • Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei, Taiwan
    • Natl Taiwan Univ

Authors

  • Keng-Yung Lin

    • Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei, Taiwan
    • Natl Taiwan Univ

  • Ko-Hsuan Chen

    • Natl Tsing Hua Univ
    • Department of Physics, National Tsing Hua University
    • Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan

  • Sheng-Wen Huang

    • Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
    • Natl Tsing Hua Univ
    • Department of Physics, National Tsing Hua University
    • Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan

  • Chao-Kai Cheng

    • Natl Taiwan Univ
    • Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan

  • Cheng-Maw Cheng

    • National Synchrotron Radiation Research Center
    • National Synchrotron Radiation Research Center, Hsinchu, Taiwan
    • Natl Synchrotron Rad Res Ctr

  • Minghwei Hong

    • Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei, Taiwan
    • Natl Taiwan Univ
    • Department of Physics, National Taiwan University
    • Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
    • Department of Physics, National Taiwan University, Taipei, Taiwan

  • Jueinai Kwo

    • Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
    • Natl Tsing Hua Univ
    • Department of Physics, National Tsing Hua University
    • Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan