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

Article

关键词: SINGLE DIRAC CONE;    PHASE-TRANSITION;    TRANSPORT;    SB2TE3;    BI2SE3;    BI2TE3;   

DOI  :  10.1103/PhysRevB.90.205432

来源: SCIE

【 摘 要 】

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 they can be probed in ellipsometry measurements.

【 授权许可】

Free