Surface and interface states of Bi$_{2}$Se$_{3}$ thin films investigated by second harmonic generation

ORAL

Abstract

Topological insulators (TIs) behave as a charge-gapped insulator in its interior, but hosting a spin-momentum-locked Dirac state at the surface. When the Fermi level crosses over conduction/valence band, undesirable bulk charge transport disturbs to exploit the surface nature, so that thin film TIs have been highlighted as a method to reduce bulk carrier effect due to large surface to volume ratio. In this presentation, we discuss surface and/or interface states for Bi$_{2}$Se$_{3}$ in form of film by exploiting second harmonic generation technique. Based on nonlinear susceptibility deduced from the model fitting, we investigate the details of band bending such as its direction and strength which were further addressed by examining terahertz field profile emitted from the sample. Finally, we discuss the evolution of these properties as a function of film thickness.

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Authors

  • S.Y. Hamh

    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
    • Gwangju Inst of Sci \& Tech

  • Soon-Hee Park

    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
    • Gwangju Inst of Sci \& Tech

  • J.S. Lee

    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
    • Gwangju Inst of Sci \& Tech

  • Jeong Heum Jeon

    • Department of Physics, Korea University, Seoul 136-713, Korea

  • Se-Jong Khang

    • Department of Physics, Korea University
    • Department of Physics, Korea University, Seoul 136-713, Korea

  • Kwangnam Yu

    • Department of Physics, University of Seoul, Seoul 130-743 Korea

  • Enjip Choi

    • Department of Physics, University of Seoul, Seoul 130-743 Korea

  • Sean Oh

    • Department of Physics and Astronomy, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
    • Rutgers University

  • Sung Kim

    • Department of Applied Physics, College of Applied Science, Kyung Hee University, Yongin 446-701, Korea

  • Suk-Ho Choi

    • Department of Applied Physics, College of Applied Science, Kyung Hee University, Yongin 446-701, Korea

  • Joonbum Park

    • Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea

  • Jun Sung Kim

    • Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea