Effects of Defects and Dephasing on Charge and Spin Currents in Two-Dimensional Topological Insulators

Abstract

Using the non-equilibrium Keldysh Green's function formalism, we investigate the effect of defects on the electronic structure and transport properties of two-dimensional topological insulators (TI). We demonstrate how the spatial flow of charge changes between the topologically protected edge and bulk states and show that elastically and inelastically scattering defects that preserve the time reversal symmetry of the TI lead to qualitatively different effects on the TI's local electronic structure and its transport properties. Moreover, we show that the recently predicted ability to create highly spin-polarized currents by breaking the time-reversal symmetry of the TI via magnetic defects [Phys. Rev. B 93, 081401 (2016)] is robust against the inclusion of a Rashba spin-orbit interaction and the effects of dephasing, and remains unaffected by changes over a wide range of the TI's parameters. We discuss how the sign of the induced spin currents changes under symmetry operations, such as reversal of bias and gate voltages, or spatial reflections. Finally, we show that the insight into the interplay between topology and symmetry of the magnetic defects can be employed for the creation of novel quantum phenomena, such as highly localized magnetic fields inside the TI.

References in corpus (36)

• Topological Insulators
• Topological insulators and superconductors
• Quantum Spin Hall Effect in Graphene
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• $Z_2$ Topological Order and the Quantum Spin Hall Effect
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Field Theory of Time-Reversal Invariant Insulators
• Novel Symmetry Classes in Mesoscopic Normal-Superconducting Hybrid Structures
• Topological invariants of time-reversal-invariant band structures
• Topological insulators and superconductors: ten-fold way and dimensional hierarchy
• Quantized Anomalous Hall Effect in Magnetic Topological Insulators
• Topological Insulator Materials
• Seeing the magnetic monopole through the mirror of topological surface states
• Magnetoelectric polarizability and axion electrodynamics in crystalline insulators
• Nonlocal edge state transport in the quantum spin Hall state
• The Helical Liquid and the Edge of Quantum Spin Hall Systems
• Quantum Anomalous Hall Effect in Hg${}_{1-y}$Mn${}_y$Te Quantum Wells
• Magnetic impurities on the surface of a topological insulator
• Spin Filtered Edge States and Quantum Hall Effect in Graphene
• Tunable symmetry breaking and helical edge transport in a graphene quantum spin Hall state
• Kondo effect in the helical edge liquid of the quantum spin Hall state
• Stacked topological insulator built from bismuth-based graphene sheet analogues
• Room Temperature Electrical Detection of Spin Polarized Currents in Topological Insulators
• Spin-Polarized Tunneling Study on Spin-Momentum Locking in the Topological Insulators
• Helical Quantum States in HgTe Quantum Dots with Inverted Band Structures
• Anomalous Hall Effects of Light and Chiral Edge Modes on the Kagome Lattice
• Rashba spin orbit coupling in the Kane-Mele-Hubbard model
• Topological insulator based spin valve devices: evidence for spin polarized transport of spin-momentum-locked topological surface states
• Breaking time reversal symmetry in topological insulators
• Spatially dependent Kondo effect in Quantum Corrals
• The fundamental differences between Quantum Spin Hall edge-states at zig-zag and armchair terminations of honeycomb and ruby nets
• Switching of electrical current by spin precession in the first Landau level of an inverted-gap semiconductor
• Electronic states induced by nonmagnetic defects in two-dimensional topological insulators
• Transport through quantum spin Hall insulator/metal junctions in graphene ribbons
• Controlling the Flow of Spin and Charge in Nanoscopic Topological Insulators
• Crossover from quantum to classical transport

Cited by in corpus (4)

• Nontrivial interplay of strong disorder and interactions in quantum spin-Hall insulators doped with dilute magnetic impurities
• Symmetry protected topological edge modes and emergent partial time reversal symmetry breaking in open quantum many-body systems
• Topological phase transition in GeSnH${}_2$ induced by biaxial tensile strain: A tight-binding study
• Spin-imbalance induced buried topological edge currents in Mott \& topological insulator heterostructures