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Bandgap Modulation in Photoexcited Topological Insulator Bi2Te3 via Atomic Displacements

MPS-Authors
/persons/resource/persons136092

Keskin,  S.
Miller Group, Atomically Resolved Dynamics Department, Max Planck Institute for the Structure and Dynamics of Matter, Max Planck Society;
The Hamburg Centre for Ultrafast Imaging, University of Hamburg, 22761 Hamburg, Germany;

/persons/resource/persons136024

Miller,  R. J. Dwayne
Miller Group, Atomically Resolved Dynamics Department, Max Planck Institute for the Structure and Dynamics of Matter, Max Planck Society;
The Hamburg Centre for Ultrafast Imaging, University of Hamburg, 22761 Hamburg, Germany;
Departments of Chemistry and Physics, University of Toronto, Toronto M5S 3H6, Canada;

External Ressource
Fulltext (public)

1.4955188.pdf
(Publisher version), 5MB

Supplementary Material (public)

supplementary information3.pdf
(Supplementary material), 1006KB

Citation

Hada, M., Norimatsu, K., Tanaka, S., Keskin, S., Tsuruta, T., Igarashi, K., et al. (2016). Bandgap Modulation in Photoexcited Topological Insulator Bi2Te3 via Atomic Displacements. The Journal of Chemical Physics, 145(2): 024504. doi:10.1063/1.4955188.


Cite as: http://hdl.handle.net/11858/00-001M-0000-002B-09B3-0
Abstract
The atomic and electronic dynamics in the topological insulator (TI) Bi2Te3 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 Bi2Te3 trigger 10% bulk bandgap narrowing, which is consistent with the time-resolved mid-infrared spectroscopy results.