Long-time relaxation dynamics of a spin coupled to a Chern insulator

The authors compute the dynamical phase diagram for the relaxation of a classical spin, exchange coupled to the local magnetic moment at an edge site of the one-dimensional spinful Su-Schrieffer-Heeger model. The role of the topological edge state and its internal Zeeman splitting for the spin-relaxation process, as well as incomplete spin relaxation on long time scales, can be explained within the framework of a renormalized linear response approach, when explicitly taking retardation effects and nonequilibrium spin-exchange processes into account.