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arXiv · 1010.0240

Magneto-optical and Magneto-electric Effects of Topological Insulators in Quantizing Magnetic Fields

Wang-Kong Tse·A. H. MacDonald
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Abstract

We develop a theory of the magneto-optical and magneto-electric properties of a topological insulator thin film in the presence of a quantizing external magnetic field. We find that low-frequency magneto-optical properties depend only on the sum of top and bottom surface Dirac-cone filling factors $ν_{\mathrm{T}}$ and $ν_{\mathrm{B}}$, whereas the low-frequency magneto-electric response depends only on the difference. The Faraday rotation is quantized in integer multiples of the fine structure constant and the Kerr effect exhibits a $π/2$ rotation. Strongly enhanced cyclotron-resonance features appear at higher frequencies that are sensitive to the filling factors of both surfaces. When the product of the bulk conductivity and the film thickness in $e^2/h$ units is small compared to $α$, magneto-optical properties are only weakly dependent on accidental doping in the interior of the film.

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Wang-Kong Tse, A. H. MacDonald. 2010-10-01. Magneto-optical and Magneto-electric Effects of Topological Insulators in Quantizing Magnetic Fields. https://doi.org/10.1103/physrevb.82.161104

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