1. THz Generation and Detection on Dirac Fermions in Topological Insulators
- Author
-
Luo, Chih Wei, Chen, Hsueh-Ju, Tu, Chien Ming, Lee, Chia Ching, Ku, Shin An, Tzeng, Wen Yen, Yeh, Tien Tien, Chiang, Meng Chi, Wang, Harn Jiunn, Chu, Wei Chen, Lin, Jiunn-Yuan, Wu, Kaung Hsiung, Juang, Jenh Yih, Kobayashi, Takayoshi, Cheng, Cheng-Maw, Chen, Ching-Hung, Tsuei, Ku-Ding, Berger, Helmuth, Sankar, Raman, Chou, Fang Cheng, and Yang, Hung Duen
- Subjects
Condensed Matter - Materials Science ,Condensed Matter::Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Mathematics::Analysis of PDEs ,Physics::Optics ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences - Abstract
This study shows that a terahertz (THz) wave can be generated from the (001) surface of cleaved Bi$_{\textrm{2}}$Se$_{\textrm{3}}$ and Cu-doped Bi$_{\textrm{2}}$Se$_{\textrm{3}}$ single crystals using 800 nm femtosecond pulses. The generated THz power is strongly dependent on the carrier concentration of the crystals. An examination of the dependence reveals the two-channel free carrier absorption to which Dirac fermions are indispensable. Dirac fermions in Bi$_{\textrm{2}}$Se$_{\textrm{3}}$ are significantly better absorbers of THz radiation than bulk carriers at room temperature. Moreover, the characteristics of THz emission confirm the existence of a recently proposed surface phonon branch that is normalized by Dirac fermions., Comment: 5 pages, 4 figures, 1 table
- Published
- 2013
- Full Text
- View/download PDF