Magneto-optical Faraday and Kerr effects in topological insulator films and in other layered quantized Hall systems

Abstract

We present a theory of the magneto-optical Faraday and Kerr effects of topological insulator (TI) films. For film thicknesses short compared to wavelength, we find that the low-frequency Faraday effect in ideal systems is quantized at integer multiples of the fine structure constant, and that the Kerr effect exhibits a giant π/2 rotation for either normal or oblique incidence. For thick films that contain an integer number of half wavelengths, we find that the Faraday and Kerr effects are both quantized at integer multiples of the fine structure constant. For TI films with bulk parallel conduction, we obtain a criterion for the observability of surface-dominated magneto-optical effects. For thin samples supported by a substrate, we find that the universal Faraday and Kerr effects are present when the substrate is thin compared to the optical wavelength or when the frequency matches a thick-substrate cavity resonance. Our theory applies equally well to any system with two conducting layers that exhibit quantum Hall effects.

Quantum Faraday and Kerr rotations in graphene

“…Further, the effect has also been predicted for graphene, where the optical-Hall effect should reflect the peculiar QHE that arises from the massless Dirac dispersion in graphene 10 . The Faraday rotation has also been anticipated for the Dirac fermions in timereversal symmetry broken topological insulators, as a consequence of magnetoelectric coupling, the effect of which can be implemented into the quantized surface Hall conductance 11,12 . Therefore, the Faraday effect in graphene provides an opportunity to test the anticipated optical-Hall effect of Dirac fermions in solids.…”

Shift charge and spin photocurrents in Dirac surface states of topological insulator

“…Not only the characterization of topological matter has been done by light-assisted experimental tools that probe electronic bands [1][2][3] and its spin textures [4,5], optical conductivities, Kerr rotation [6][7][8][9][10], Farady effect [8][9][10][11], etc, but also light plays active roles to dynamically induce topological phase transitions [12][13][14][15][16][17] and generates a new type of topological excitations [18].…”

Infrared probe of the bulk insulating response inBi2−xSbxTe3−yPost1, Lee2, Chapler3 et al. 2015Phys. Rev. B181110View full textAdd to dashboardCite

“…The SSs in TIs are unique in that they host electrons that are resistant to direct backscattering and localization [2,4,5]. Moreover, SSs possess unique magnetoelectric properties that are predicted to yield a number of exotic effects, including an induced magnetic monopole, and quantized Kerr rotation [18][19][20][21][22][23]. It has also been proposed that these numerous exotic properties of SSs could be utilized in a plethora of technologies including quantum computing, spintronics, and improving current computer technology [15].…”