Resonant Faraday and Kerr effects due to in-gap states on the surface of a topological insulator

Abstract

When Dirac electrons on the surface of a topological insulator are gapped, the resulting quantum anomalous Hall effect leads to universal magneto-optical Faraday and Kerr effects in the low frequency limit. However, at higher frequencies different excitations can leave their own fingerprints on the magneto-optics and can therefore be probed. In particular, we investigate the role of localized in-gap states---which inevitably appear in the presence of charged impurities---on these higher frequency magneto-optical effects. We have shown that these states resonantly contribute to the Hall conductivity and are magneto-optically active. These in-gap states lead to peculiar resonant signatures in the frequency dependence of the Faraday and Kerr angles, distinct in character to the contribution of in-gap excitonic states, and can be probed in ellipsometry measurements.

10 pages, 10 figures, updated following the peer review process

References in corpus (22)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Non-Abelian Anyons and Topological Quantum Computation
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• Topological Field Theory of Time-Reversal Invariant Insulators
• Nonlocal edge state transport in the quantum spin Hall state
• The Helical Liquid and the Edge of Quantum Spin Hall Systems
• The development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3
• Vacuum Polarization and Screening of Supercritical Impurities in Graphene
• Atomic Collapse and Quasi-Rydberg States in Graphene
• Electronic Structures and Surface States of Topological Insulator Bi${}_{1-x}$Sb${}_x$
• Supercritical Coulomb center and excitonic instability in graphene
• Terahertz Kerr and Reflectivity Measurements on the Topological Insulator Bi2Se3
• Terahertz Quantum Hall Effect in a Topological Insulator
• Excitons and Optical Absorption on the Surface of a Strong Topological Insulator with a Magnetic Energy Gap
• Optical properties of magnetically doped ultra-thin topological insulator slabs
• Dirac cone shift of a passivated topological Bi2Se3 interface state
• Generalized quantization condition in topological insulator
• Giant plateau in the THz Faraday angle in gated Bi2Se3

Cited by in corpus (7)

• Photogalvanic effect in HgTe/CdTe topological insulator due to edge-bulk optical transitions
• Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures
• Resonant optical topological Hall conductivity from skyrmions
• Unusual spin dynamics in topological insulators
• Transport of Dirac electrons in a random magnetic field in topological heterostructures
• Observation of topological Faraday and Kerr rotations in quantum anomalous Hall state by terahertz magneto-optics
• Electromagnon on the Surface of Magnetic Topological Insulator