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F14: Electronic Structure of Topological Materials (Photoemission, etc.) I

M100E

Sponsoring Units: DCMPChair: Madhab Neupane, University of Central Florida

Tue. March 5, 8:00 a.m. – 8:12 a.m. CST

M100E

Nonsymmorphic symmetries, such as screw rotations and glide reflections, can induce characteristic nodal lines or surfaces in the band dispersions of crystals. However, since the nonsymmorphic symmetries responsible for the formation of the nodal lines may not be maintained in the surface region, the crystal surface may host a different electronic structure from the bulk.

In this presentation, we present an extensive ARPES study of the differences between the near-surface electronic structure and the bulk structure hosting nodal lines. Due to electron scattering processes, ARPES can only capture the near-surface electronic structure of a crystal up to a depth of a few nanometers from the surface. We examine the near-surface electronic structure of
$AB$-stacked $2H$-$mathrm{Nb}mathrm{S}_2$ and $h$BN crystals, both of which host bulk nodal lines on the $k_z=pi/c$ plane. We found gapped band dispersions on the $k_z=pi/c$ plane, indicating that the broken screw rotational symmetry at the surface opens an energy gap in the near-surface electronic structure. Taking into account the surface sensitivity of ARPES, our photoemission intensity calculations [1] could reproduce such gapped spectra by adjusting the probing depth parameter in the simulation. Our results show that incomplete nonsymmorphic symmetries can alter the near-surface electronic structure associated with the bulk nodal lines [2].

Presented By

  • Hiroaki Tanaka (The University of Tokyo)

Authors

  • Hiroaki Tanaka (The University of Tokyo)
  • Shota Okazaki (Tokyo Institute of Technology)
  • Masaru Kobayashi (Tokyo Institute of Technology)
  • Yuto Fukushima (The University of Tokyo)
  • Yosuke Arai (The University of Tokyo)
  • Takushi Iimori (The University of Tokyo)
  • Mikk Lippmaa (The University of Tokyo)
  • Kohei Yamagami (Japan Synchrotron Radiation Research Institute)
  • Yoshinori Kotani (Japan Synchrotron Radiation Research Institute)
  • Fumio Komori (The University of Tokyo)
  • Kenta Kuroda (Hiroshima University)
  • Takao Sasagawa (Tokyo Institute of Technology)
  • Takeshi Kondo (The University of Tokyo)