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

## TL;DR

This paper reveals a $ ext{Z}_2$ non-Hermitian skin effect in equilibrium heavy-fermion systems with time-reversal symmetry, showing how spin-orbit coupling and temperature influence the localization of quasi-particle modes.

## Contribution

It introduces the concept of a $ ext{Z}_2$ non-Hermitian skin effect in correlated electron systems and demonstrates its dependence on spin-orbit interaction and temperature through DMFT analysis.

## Key findings

- Existence of $ ext{Z}_2$ skin effect in equilibrium $f$-electron systems.
- Spin-orbit coupling is crucial for the skin effect.
- Skin modes are localized above the Kondo temperature.

## 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.