# Disorder-induced exceptional and hybrid rings in Weyl/Dirac semimetals

## TL;DR

This paper explores how disorder in Weyl and Dirac semimetals induces exceptional rings and flat bands, revealing new non-Hermitian topological phenomena observable via experimental techniques.

## Contribution

It demonstrates that disorder causes Weyl exceptional rings and hybrid structures in Weyl/Dirac semimetals, expanding non-Hermitian physics to disordered systems.

## Key findings

- Disorder induces Weyl exceptional rings regardless of scattering details.
- Hybrid rings and flat bands are realized in Dirac semimetals.
- Effects are detectable via photoemission and quasiparticle interference.

## Abstract

Non-Hermiticity in Weyl Hamiltonian leads to the realization of Weyl exceptional rings and flat bands inside the Weyl exceptional rings. Recently, the platform of non-Hermitian physics is extended to many-body or disordered systems where quasiparticles possess finite lifetime. Here, we clarify that the deviation from unitarity limit in a disordered Weyl semimetal leads to the generation of Weyl exceptional rings regardless of the detail of the scattering potential. In the case of topological Dirac semimetals, hybrid rings and flat bands without vorticity of complex-energy eigenvalues are realized. This scenario is applicable to any Weyl or Dirac semimetals. These effects are detectable by using photoemission or quasiparticle interference experiments.