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Proceedings Paper

Nonlinear terahertz dynamics of Dirac electrons in Bi thin films
Author(s): Ikufumi Katayama; Yasuo Minami; Yusuke Arashida; Orjan Sele Handegard; Tadaaki Nagao; Masahiro Kitajima; Jun Takeda
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Paper Abstract

By using both linear and nonlinear terahertz spectroscopy on epitaxial Bi and Bi1-xSbx thin films, we systematically investigated the linear and nonlinear terahertz dynamics of Dirac electrons. The linear terahertz transmittance was analyzed by the Drude model up to 50 THz, and then the plasma frequency and the damping constant were evaluated as functions of the film thickness and Sb-concentration. We found surface metallic state for Bi ultra-thin films, while semimetal to semiconductor crossover for Bi1-xSbx thin films. In the nonlinear terahertz spectroscopy, the terahertz transmittance increases with increasing the field strength, which could be assigned to the carrier acceleration along the Dirac-like band dispersion at the L point in the Brillouin zone. In addition, we observed the terahertz-induced absorption in terahertz-pump and terahertz-probe spectroscopy, which could be assigned to carrier generation due to Zener tunneling in Dirac band structure. The results demonstrate that Bi-related materials are promising candidates for future nonlinear terahertz devices.

Paper Details

Date Published: 14 September 2018
PDF: 7 pages
Proc. SPIE 10756, Terahertz Emitters, Receivers, and Applications IX, 107560P (14 September 2018); doi: 10.1117/12.2320801
Show Author Affiliations
Ikufumi Katayama, Yokohama National Univ. (Japan)
Yasuo Minami, Yokohama National Univ. (Japan)
Tokushima Univ. (Japan)
Yusuke Arashida, Yokohama National Univ. (Japan)
Orjan Sele Handegard, National Institute for Materials Science (Japan)
Hokkaido Univ. (Japan)
Tadaaki Nagao, National Institute for Materials Science (Japan)
Hokkaido Univ. (Japan)
Masahiro Kitajima, Yokohama National Univ. (Japan)
National Institute for Materials Science (Japan)
Jun Takeda, Yokohama National Univ. (Japan)

Published in SPIE Proceedings Vol. 10756:
Terahertz Emitters, Receivers, and Applications IX
Manijeh Razeghi; Alexei N. Baranov, Editor(s)

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