Ultrafast Carrier Dynamics and Light-Induced Functionalizations of Topological Insulators

Abstract

By using time- and angle-resolved photoemission spectroscopy, we investigate the ultrafast carrier dynamics in the series of (Sb, Bi)₂ Te₃. We show that the electronic recovery time for the surface Dirac fermions is prolonged to >400 ps when the charge neutrality point is approached. We also discuss the emergence of light-induced functionalizations such as surface photovoltage effect in the ultrafast time-domain. Our study strengthens the route toward the Dirac materials to be an opto-spintronic application.