THz Generation and Detection on Dirac Fermions in Topological Insulators

C. W. Luo; C. C. Lee; H. -J. Chen; C. M. Tu; S. A. Ku; W. Y. Tzeng; T. T. Yeh; M. C. Chiang; H. J. Wang; W. C. Chu; J. -Y. Lin; K. H. Wu; J. Y. Juang; T. Kobayashi; C. -M. Cheng; C. -H. Chen; K. -D. Tsuei; H. Berger; R. Sankar; F. C. Chou; H. D. Yang

THz Generation and Detection on Dirac Fermions in Topological Insulators

Mesoscale and Nanoscale Physics 2013-02-06 v1 Materials Science

Authors: C. W. Luo , C. C. Lee , H. -J. Chen , C. M. Tu , S. A. Ku , W. Y. Tzeng , T. T. Yeh , M. C. Chiang , H. J. Wang , W. C. Chu , J. -Y. Lin , K. H. Wu , J. Y. Juang , T. Kobayashi , C. -M. Cheng , C. -H. Chen , K. -D. Tsuei , H. Berger , R. Sankar , F. C. Chou , H. D. Yang

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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.

Keywords

terahertz radiation

Cite

@article{arxiv.1302.1087,
  title  = {THz Generation and Detection on Dirac Fermions in Topological Insulators},
  author = {C. W. Luo and C. C. Lee and H. -J. Chen and C. M. Tu and S. A. Ku and W. Y. Tzeng and T. T. Yeh and M. C. Chiang and H. J. Wang and W. C. Chu and J. -Y. Lin and K. H. Wu and J. Y. Juang and T. Kobayashi and C. -M. Cheng and C. -H. Chen and K. -D. Tsuei and H. Berger and R. Sankar and F. C. Chou and H. D. Yang},
  journal= {arXiv preprint arXiv:1302.1087},
  year   = {2013}
}

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5 pages, 4 figures, 1 table

THz Generation and Detection on Dirac Fermions in Topological Insulators

Abstract

Keywords

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