Seifert Paul, Vaklinova Kristina, Kern Klaus, Burghard Marko, Holleitner Alexander
Walter Schottky Institut and Physik-Department, Technische Universität München , Am Coulombwall 4a, D-85748 Garching, Germany.
Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, D-70569 Stuttgart, Germany.
Nano Lett. 2017 Feb 8;17(2):973-979. doi: 10.1021/acs.nanolett.6b04312. Epub 2017 Jan 18.
Topological insulators constitute a fascinating class of quantum materials with nontrivial, gapless states on the surface and insulating bulk states. By revealing the optoelectronic dynamics in the whole range from femto- to microseconds, we demonstrate that the long surface lifetime of BiTeSe nanowires allows us to access the surface states by a pulsed photoconduction scheme and that there is a prevailing bolometric response of the surface states. The interplay of the surface and bulk states dynamics on the different time scales gives rise to a surprising physical property of BiTeSe nanowires: their pulsed photoconductance changes polarity as a function of laser power. Moreover, we show that single BiTeSe nanowires can be used as THz generators for on-chip high-frequency circuits at room temperature. Our results open the avenue for single BiTeSe nanowires as active modules in optoelectronic high-frequency and THz circuits.
拓扑绝缘体是一类迷人的量子材料，其表面具有非平凡的无隙态，而体相是绝缘态。通过揭示从飞秒到微秒整个范围内的光电动力学，我们证明了BiTeSe纳米线的长表面寿命使我们能够通过脉冲光电导方案访问表面态，并且表面态存在主导的热辐射响应。表面态和体相态在不同时间尺度上的相互作用产生了BiTeSe纳米线令人惊讶的物理性质：它们的脉冲光电导随激光功率的变化而改变极性。此外，我们表明单个BiTeSe纳米线可在室温下用作片上高频电路的太赫兹发生器。我们的结果为单个BiTeSe纳米线作为光电高频和太赫兹电路中的有源模块开辟了道路。
