2013/01/26 by Chih‐Wei Luo, C. W. Luo, C. C. Lee +52
Engineering · Physics and Astronomy · #Superconducting and THz Device Technology #Terahertz technology and applications #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.1302.1087
5 pages, 4 figures, 1 table
arxiv created 2013/01/26 · arxiv updated 2013/02/06
This study shows that a terahertz (THz) wave can be generated from the (001) surface of cleaved Bi_\textrm2Se_\textrm3 and Cu-doped Bi_\textrm2Se_\textrm3 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_\textrm2Se_\textrm3 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.