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Evolution of the band structure of α-Sn(001) thin film on InSb(001)

ORAL

Abstract

Determining the topological phase of a material is a popular research route in condensed matter physics. For elemental material of α-Sn, its topological phase has been under debate. α-Sn(001) with in-plane compressive strain is expect to be a topological Dirac semimetal in theory, but experimental evidence of 3D Dirac state is still lacking. In contrast, a spin-momentum locked topological surface state (TSS) was found for α-Sn(001) on InSb(001), suggesting a topological insulator (TI). In this work, molecular beam epitaxy grown α-Sn(001) on InSb(001) and the thickness dependent angle-resolved photoemission spectroscopy (ARPES) study from 3 bilayers (BLs) to 370 BLs are reported. Streaky (2×1) reflection high energy electron diffraction patterns and narrowθ-rocking curve (FWHM of 0.0163°) in x-ray diffraction indicated an excellent crystallinity. Sharp TSSs were attained by ARPES in films thicker than 6 BLs without resorting to extra doping or surface treatments. No TSSs were observed for film thinner than 5 BLs, indicating a crossover from 3D TI to trivial insulator. In an extremely thick α-Sn film of 370 BLs, no evident kz dependence on the Dirac state was found in photon energy range of 10-40 eV, suggesting α-Sn(001) on InSb(001) more likely to be in TI phase.

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Presenters

  • Ko-Hsuan Chen

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

Authors

  • Ko-Hsuan Chen

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

  • Keng-Yung Lin

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

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

  • Hsiao-Yu Lin

    Department of Physics, National Tsing Hua University

  • Shang-Wei Lien

    Department of Physics, National Cheng Kung University

  • Tay-Rong Chang

    National Cheng Kung University, Physics, National Cheng Kung University, Department of Physics, National Cheng Kung University, National Cheng Kung University, 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