標題: Snapshots of Dirac Fermions near the Dirac Point in Topological Insulators
作者: Luo, C. W.
Wang, H. J.
Ku, S. A.
Chen, H. -J.
Yeh, T. T.
Lin, J. -Y.
Wu, K. H.
Juang, J. Y.
Young, B. L.
Kobayashi, T.
Cheng, C. -M.
Chen, C. -H.
Tsuei, K. -D.
Sankar, R.
Chou, F. C.
Kokh, K. A.
Tereshchenko, O. E.
Chulkov, E. V.
Andreev, Yu. M.
Gu, G. D.
電子物理學系
物理研究所
Department of Electrophysics
Institute of Physics
關鍵字: Topological insulator;ultrafast optical pump mid-infrared probe spectroscopy;Dirac fermion dynamics;Dirac fermion-phonon coupling
公開日期: 1-Dec-2013
摘要: The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to 4 explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.
URI: http://dx.doi.org/10.1021/nl4021842
http://hdl.handle.net/11536/23446
ISSN: 1530-6984
DOI: 10.1021/nl4021842
期刊: NANO LETTERS
Volume: 13
Issue: 12
起始頁: 5797
結束頁: 5802
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