Quantitative theory of backscattering in topological HgTe and (Hg,Mn)Te quantum wells: Acceptor states, Kondo effect, precessional dephasing, and bound magnetic polaron

Which mechanism accounts for backscattering between helical edge states in two-dimensional topological insulators? Here and in a companion paper Phys. Rev. Lett. 130, 086202 (2023), the author demonstrates that the magnitude of the topological protection length can be explained by spin nonconserving Kondo scattering of edge electrons by holes, localized on background acceptors and residing in the band gap. Surprisingly, doping with Mn ions restores the quantization precision due to the formation of acceptor-bound magnetic polarons that destroy the Kondo effect.