Probing non-Hermitian effects on weak localization and antilocalization through dissipative topological surface states
Phys. Rev. B 113, 035439 – Published 27 January, 2026
DOI: https://doi.org/10.1103/26rv-1rd7
Abstract
The quantum interference effect arises from conduction electrons moving along time-reversed electron scattering paths in disordered systems, which leads to weak localization (WL) and antilocalization (WAL) behaviors that suppress and enhance the conductivity, respectively. The research on this effect has so far primarily focused on Hermitian systems, where it is dictated by multiple factors such as symmetry class, dimensionality, interband coupling, band topology, and the nature of disorder potential. However, many realistic systems are intrinsically non-Hermitian due to loss and/or gain from interactions with the external environment. This non-Hermiticity induces complex energy phases into scattering processes, fundamentally modifying electron phase coherence and thereby necessitating a reexamination of quantum interference. Here we investigate the impact of non-Hermiticity on WL and WAL through dissipative topological surface states, and we uncover an underlying connection between symmetry classification and quantum interference behavior. In symmetry class AIII, the geometry of scattering paths, distinguished by their real and imaginary energy components, induces negative Cooperon gaps absent in conventional Hermitian counterparts, whose combination with non-Hermitian topology gives rise to multiple crossovers between WL and WAL, manifesting as alternating variations in positive and negative magnetoconductivities. The corresponding WL and WAL phase diagram reveals the robustness of these crossovers against variations in temperature and magnetic field. As the system transitions from class AIII to class or class A, the entanglement of the real and imaginary energy scatterings obliterates the crossover structure, leaving only WAL-type magnetoconductivity. Using realistic material parameters, we show that the non-Hermiticity-induced quantum interference phenomena should be experimentally observable.
