09-61 Emil Prodan
Robustness of the Spin-Chern number: An analytic proof (259K, PDF) Apr 13, 09
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Abstract. Ever since introduced, the topological properties of the Spin-Chern ($C_s$) have been discussed and re-discussed in a fairly large number of works. On one hand the original paper by Sheng and collaborators revealed robust properties of $C_s$ against disorder and certain deformations of the model and, on the other hand, other people pointed out that $C_s$ can change sign under special deformations that keep the insulating gap open. This makes one wonder how far does the robustness observed in the original paper extend? In this paper we give an analytic result that allows us to state in extremely simple terms the origin of the robustness against disorder and continuous local deformations of the models. It also allows us to give several generalizations of the topological invariant.

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