Topology and localization in the Kondo lattice model*

The Kondo lattice model describing the coupling between conduction electrons and localized magnetic moments is relevant for a large family of physical systems. Here we reveal that the one-dimensional Kondo lattice model with a magnetic elliptical spiral is a topological insulator with a Chern number 2Z in the two-dimensional space with one physical dimension and one ancillary dimension spanned by the Goldstone mode of the spiral. The 2Z topological classification can be reduced to Z if certain spin rotation symmetry is broken. Moreover, when the elliptical spiral is incommensurate, the electronic states can be localized for a strong local exchange coupling. The topological protected edge states are responsible for the pumping of electron charge, and give rise to multiferroic response. The coexistence of nontrivial band topology and Anderson localization results in a unique charge pumping. Our work uncovers hitherto undiscovered nontrivial topology and Anderson localization in the Kondo lattice model.
Ref: Ying Su and Shi-Zeng Lin, arXiv:1809.06295 (2018).