Defective Majorana zero modes in non-Hermitian Kitaev chain

TL;DR

This paper explores how non-Hermitian effects influence the stability and properties of Majorana zero modes in a Kitaev chain, revealing phenomena like defective MZMs and anomalous bulk-boundary correspondence.

Contribution

It introduces the concept of defective Majorana zero modes in a non-Hermitian Kitaev chain and analyzes their unique topological and magnetic properties.

Findings

Identification of defective MZMs due to non-Hermitian coalescence

Discovery of number-anomalous bulk-boundary correspondence

Observation of magnetic phase crossover without gap closing

Abstract

Topological stability is an important property for topological materials. However, the non-Hermitian effects may change this situation. Here, we investigate the robustness of edge states in the non-Hermitian Kitaev chain with imbalanced tunneling term and superconducting pairing term. By defining the similarity of Majorana zero modes (MZMs) and magnetic factor, the coalescing phase diagram of the MZMs and corresponding spin polarization phase diagram are provided. Because of the non-Hermitian coalescence effect and non-Hermitian suppression effect induced by the breakdown of sublattice symmetry and particle-hole symmetry, the system emergence very interesting phenomenons, such as defective MZMs, number-anomalous bulk-boundary correspondence, coalescing of many-body ground states, the magnetic phase crossover without gap closing. Those novel non-Hermitian effects offer fresh insights into MZMs and topological physics.