${\mathbb{Z}}_2$ Non-Hermitian skin effect in equilibrium heavy-fermions

Abstract

We demonstrate that a correlated equilibrium $f$-electron system with time-reversal symmetry can exhibit a ${\mathbb{Z}}_2$ non-Hermitian skin effect of quasi-particles. In particular, we analyze a two-dimensional periodic Anderson model with spin-orbit coupling by combining the dynamical mean-field theory (DMFT) and the numerical renormalization group. We prove the existence of the ${\mathbb{Z}}_2$ skin effect by explicitly calculating the topological invariant and show that spin-orbit interaction is essential to this effect. Our DMFT analysis demonstrates that the ${\mathbb{Z}}_2$ skin effect of quasi-particles is reflected on the pseudo-spectrum. Furthermore, we analyze temperature effects on this skin effect using the generalized Brillouin zone technique, which clarifies that the skin modes are strongly localized above the Kondo temperature.

12 pages, 9 figures. References are updated. Published in PRB