Abstract
Topological insulators can exhibit strong magneto-electric effects when their time-reversal symmetry is broken. In this Letter we consider the magneto-optical Kerr and Faraday effects of a topological insulator thin film weakly exchange coupled to a ferromagnet. We find that its Faraday rotation has a universal value at low frequencies , where is the vacuum fine structure constant, and that it has a giant Kerr rotation . These properties follow from a delicate interplay between thin-film cavity confinement and the surface Hall conductivity of a topological insulator’s helical quasiparticles.
- Received 28 February 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.057401
©2010 American Physical Society
Viewpoint
Berry’s phase and quantization in topological insulators
Published 26 July 2010
The exactly quantized magneto-optical response of a topological insulator is a direct result of the Berry phase protected states on its surface.
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