Real-space topological localizer index to fully characterize the dislocation skin effect

TL;DR

This paper introduces a real-space topological invariant using the spectral localizer to predict and characterize the dislocation skin effect in 2D non-Hermitian systems, applicable to both ordered and disordered lattices.

Contribution

It presents a novel real-space topological invariant that unifies the diagnosis of boundary and dislocation skin effects in complex systems.

Findings

Invariant predicts skin effect occurrence and location

Applicable to disordered and ordered systems

Unifies boundary and dislocation skin effect analysis

Abstract

The dislocation skin effect exhibits the capacity of topological defects to trap an extensive number of modes in two-dimensional non-Hermitian systems. Similar to the corresponding skin effects caused by system boundaries, this phenomenon also originates from nontrivial topology. However, finding the relationship between the dislocation skin effect and nonzero topological invariants, especially in disordered systems, can be obscure and challenging. Here, we introduce a real-space topological invariant based on the spectral localizer to characterize the skin effect on two-dimensional lattices. We demonstrate that this invariant consistently predicts the occurrence and location of both boundary and dislocation skin effects, offering a unified approach applicable to both ordered and disordered systems. Our work demonstrates a general approach that can be utilized to diagnose the topological nature of various types of skin effects, particularly in the absence of translational symmetry when momentum-space descriptions are inapplicable.