![]() 1) will give rise to a correction to the conductivity. In this regime, the quantum interference between time-reversed scattering loops (see Fig. If ℓ ϕ ≫ ℓ, electrons will maintain their phase coherence even after being scattered for many times, referring to as the quantum diffusive regime. In the diffusive regime, if ℓ ϕ ≤ ℓ, we call it the semiclassical diffusion, and this part gives the Drude conductivity. In the opposite limit ℓ ≪ L, electrons will suffer from scattering and diffuse through the sample, and this is the diffusive transport regime. If ℓ ≫ L, electrons can tunnel through the sample without being scattered. The open circles represent impurities and arrows mark the trajectories that electron travelled. 2 Weak Localization and Anti-Localization 2.1 Quantum diffusion Figure 1: Schematic illustration of different electronic transport regimes in solids. 6, we will explain how the contradictory observations in the temperature and magnetic field dependence of the conductivity of topological insulators can be understood, by including both the quantum interference and electron-electron interactions for the disordered Dirac fermions. 5, we compare the Dirac fermions with conventional electrons, on their localization behaviors in the presence of three kinds of disorder scattering. 4, we show why the bulk states in topological insulator can have weak localization. 3, we discuss the crossover between weak anti-localization and weak localization and the Berry phase argument. Then the experiments of weak anti-localization in topological insulators are reviewed. 2, we give an introduction to the quantum diffusion regime, where the weak (anti-)localization happens. Here we review our recent efforts on the theoretical understanding to the weak localization and weak anti-localization effects in the transport experiments in topological insulators. Finally, we show that both the interaction and quantum interference are required to account for the experimentally observed temperature and magnetic field dependence of the conductivity at low temperatures. We compare the localization behaviors of Dirac fermions with conventional electron systems in the presence of disorders of different symmetries. The bulk states in a topological insulator thin film can exhibit the weak localization effect, quite different from other system with strong spin-orbit interaction. We predicted a crossover from weak anti-localization to weak localization if the massless Dirac fermions (such as the surface states of topological insulator) acquire a Dirac mass, which was confirmed experimentally. In this article, we review recent progresses in both theory and experiment of weak (anti-)localization in topological insulators, where the quasiparticles are described as Dirac fermions. These effects have been widely observed in topological insulators. A magnetic field can destroy the quantum interference effect, giving rise to a cusp-like positive and negative magnetoconductivity as the signatures of weak localization and weak anti-localization, respectively. Weak anti-localization enhances the conductivity and weak localization suppresses the conductivity with decreasing temperature at very low temperatures. National Research Council of Canada.Weak localization and weak anti-localization are quantum interference effects in quantum transport in a disordered electron system.Weak antilocalization effect in high-mobility two-dimensional electron gas in an inversion layer on p-type HgCdTe DOI
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |