Dynamic impurities in two-dimensional topological insulator-edge states

Abstract

Helical edge states of two-dimensional topological insulators show a gap in the density of states (DOS) and suppressed conductance in the presence of ordered magnetic impurities. Here we will consider the dynamical effects on the DOS and transmission when the magnetic impurities are driven periodically. Using the Floquet formalism and Green's functions, the system properties are studied as a function of the driving frequency and the potential energy contribution of the impurities. We see that increasing the potential part closes the DOS gap for all driving regimes. The transmission gap is also closed, showing a pronounced asymmetry as a function of energy. These features indicate that the dynamical transport properties could yield valuable information about the magnetic impurities.

10 pages, 8 figures

References in corpus (12)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• The Helical Liquid and the Edge of Quantum Spin Hall Systems
• Kondo effect in the helical edge liquid of the quantum spin Hall state
• Edge Dynamics in a Quantum Spin Hall State: Effects from Rashba Spin-Orbit Interaction
• Conductance of a helical edge liquid coupled to a magnetic impurity
• Resistance of helical edges formed in a semiconductor heterostructure
• Conductivity of a generic helical liquid
• Renormalization group approach for the scattering off a single Rashba impurity in a helical liquid
• Filling of magnetic-impurity-induced gap in topological insulators by potential scattering
• Quantum Hall edge states under periodic driving: a Floquet induced chirality switch
• Nearly perfect spin-filtering in curved two-dimensional topological insulators