Many-impurity scattering on the surface of a topological insulator

Abstract We theoretically address the impact of a random distribution non-magnetic impurities on electron states formed at surface topological insulator. The interaction electrons with is accounted for by separable pseudo-potential method that allows us to obtain closed expressions density states. Spectral properties are assessed means Green’s function averaged over disorder realisations. For comparison purposes, configurationally calculated two different self-consistent methods, namely Born approximation (SCBA) and coherent potential (CPA). latter often regarded as best single-site theory study spectral disordered systems. However, although large number works employ SCBA analysis many-impurity scattering insulator, CPA studies same problem scarce in literature. In this work, we find overestimates compared predictions. difference more pronounced when increasing magnitude disorder.