Ultrafast Dynamics of Bi1.5Sb0.5Te1.8Se1.2 Topological Insulator
Abstract
Bi1.5Sb0.5Te1.8Se1.2 (BSTS) is a type of topological insulator, which is an insulator in bulk but surface states are gapless. In this work, we took optical pump-probe data on BSTS crystal to analyze the dynamics of phonons and charge carriers. The ultrafast dynamics were obtained as a function of temperature ranging from 10K to 300K, as well as fluence ranging from 1 μJ/cm2 to 10 μJ/cm2. In additional to the coherent optical phonon mode found in other topological insulators, acoustic phonon mode was observed in our experiment. We also observed phonon softening and the temperature dependence of carrier lifetime in BSTS.
Singapore NRF RCA-08/018 and NRF-CRP4-2008-04; Singapore MOE AcRF Tier 1 RG 13/12, Tier 2 MOE2010-T2-2-059 and ARC 23/08; NNSA of US DOE at LANL under Contract No. DE-AC52-06NA25396, and in part by LANL CINT, a US DOE Office of BES user facility.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2014
- Bibcode:
- 2014APS..MARA42010C