2014/03/11 by Yoshito Onishi, Zhi Ren, Onishi, Yoshito +10
Engineering · Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optics (physics.optics) #Photorefractive and Nonlinear Optics #Terahertz technology and applications #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.mtrl-sci #physics.optics
paper · pdf · doi:10.48550/arxiv.1403.2492
20 pages, 5 figures
openalex publication_date 2014/03/11 · arxiv created 2015/03/30 · arxiv updated 2015/03/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Topological insulator materials have been extensively studied in the field of condensed matter physics because nontrivial topology in the electronic state gives rise to a novel spin-polarized Dirac dispersion on the surface. To describe the electrodynamics of topological insulators, it is crucial to understand coherent and incoherent dynamics of carriers both in bulk and surface states. We applied terahertz emission spectroscopy to an intrinsic three-dimensional topological insulator material, Bi1.5 Sb0.5 Te1.7 Se1.3, to elucidate ultrafast photo-induced carrier dynamics. The emitted terahertz electric field strongly depended on the polarization and incident angle of the excitation pulse. A three-fold rotational symmetry was clearly confirmed in the dependence of terahertz emissions on the azimuthal angle. The origin of terahertz emissions should be instantaneous photon drag currents induced by the excitation of femtosecond pulses.