TRANSPORT PROPERTIES OF 3D TOPOLOGICAL INSULATORS

Abstract

Three-dimensional (3D) topological insulators (TIs) are a newly discovered state of matter with insulating bulk and conducting surfaces, which are protected from backscattering by time reversal symmetry. The surface currents are spin-polarized, thus making them exciting candidates for spintronic applications. The most commonly studied TI material to date is Bi2Se3. The major experimental issue facing the transport characterization of TIs is the non-insulating nature of the bulk, which makes the access to the conducting surface state extremely challenging. This thesis studies the transport properties of 3D TIs. It investigates the immunity of the conducting surface states to external disorder, and finds them to be quite robust. It further studies the effect of ionic liquid gating on TIs and finds large modulation at room temperature. It also finds signatures of magnetic proximity in TIs interfaced with magnetic insulators and studies the proximity effect in detail.