1201.5708 (Alexander Selem)
Alexander Selem
Results are presented for anomalous currents on the surface of topological
insulators with ferromagnetic time-reversal breaking mass terms on fully closed
topologies. Half-integer quantized Hall currents are computed using Dirac
energy eigenstates on a flat torus (genus one topology) and closed cap cylinder
(genus zero topology) with various massive regions and electromagnetic sources
applied. Unlike the massive Dirac theory on an infinite plane with anomaly
dependence $|m|/m$, one finds a smooth dependence when the mass-region strength
is not infinite. This dependence could be measurable for typical ferromagnetic
materials and crystal sizes. Issues related to charge transport, gap-crossing
bands, and flux threading are discussed and clarified for different mass
geometries. Finally, in light of the results for various mass configurations, a
construction is proposed using ferromagnetic mass terms that can serve as a
potential charged qubit.
View original:
http://arxiv.org/abs/1201.5708
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