Bandgap modulation in photoexcited topological insulator Bi{sub 2}Te{sub 3} via atomic displacements

Journal Article · Thu Jul 14 00:00:00 EDT 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4955188· OSTI ID:22675973

Hada, Masaki ^[1]; Norimatsu, Katsura; Tsuruta, Tetsuya; Igarashi, Kyushiro; Kayanuma, Yosuke; Sasagawa, Takao; Nakamura, Kazutaka G. ^[2]; Tanaka, Sei'ichi; Ishikawa, Tadahiko; Koshihara, Shin-ya ^[3]; Keskin, Sercan ^[4]; Miller, R. J. Dwayne ^[4]; Onda, Ken ^[5]

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1. Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530 (Japan)
2. Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)
3. Department of Chemistry and Materials Science, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)
4. The Max Planck Institute for the Structure and Dynamics of Matter, The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Hamburg 22761 (Germany)
5. PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

The atomic and electronic dynamics in the topological insulator (TI) Bi{sub 2}Te{sub 3} under strong photoexcitation were characterized with time-resolved electron diffraction and time-resolved mid-infrared spectroscopy. Three-dimensional TIs characterized as bulk insulators with an electronic conduction surface band have shown a variety of exotic responses in terms of electronic transport when observed under conditions of applied pressure, magnetic field, or circularly polarized light. However, the atomic motions and their correlation between electronic systems in TIs under strong photoexcitation have not been explored. The artificial and transient modification of the electronic structures in TIs via photoinduced atomic motions represents a novel mechanism for providing a comparable level of bandgap control. The results of time-domain crystallography indicate that photoexcitation induces two-step atomic motions: first bismuth and then tellurium center-symmetric displacements. These atomic motions in Bi{sub 2}Te{sub 3} trigger 10% bulk bandgap narrowing, which is consistent with the time-resolved mid-infrared spectroscopy results.

• OSTI ID: 22675973
• Journal Information: Journal of Chemical Physics, Vol. 145, Issue 2; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ATOMIC DISPLACEMENTS
BISMUTH TELLURIDES
ELECTRON DIFFRACTION
ELECTRONIC STRUCTURE
MAGNETIC FIELDS
THREE-DIMENSIONAL LATTICES
TIME RESOLUTION