Topological superconducting phase in a non-Hermitian Kitaev chain with staggered pairing imbalance

TL;DR

This paper explores a non-Hermitian Kitaev chain with staggered pairing imbalance, revealing how tuning parameters induces topological phases with Majorana modes and complex spectral transitions.

Contribution

It introduces a novel non-Hermitian model with staggered pairing imbalance, analytically characterizes phase boundaries, and demonstrates the emergence of topological superconductivity and Majorana modes.

Findings

Spectral gap transitions from real to imaginary with parameter tuning.

Pairing imbalance enlarges the topological phase region.

Majorana zero modes can be induced even at high chemical potential.

Abstract

We introduce a one-dimensional non-Hermitian Kitaev chain with staggered imbalance in the $p$-wave superconducting pairing. By tuning the chemical potential and the pairing imbalance, we find that the eigenenergy spectrum undergoes real-to-complex transitions, and the spectral gap can change from a real to an imaginary one. The pairing imbalance significantly enlarges the parameter region supporting a topological superconducting phase. Remarkably, we show that a topologically nontrivial phase hosting Majorana zero modes can be induced by varying the pairing imbalance, even in the regime of strong chemical potential. The gap-closing points and phase boundaries are determined analytically, and the resulting phase diagrams are presented with the nontrivial phase characterized by a nonzero topological invariant. Furthermore, we identify the coexistence of Majorana zero modes and finite-energy Majorana edge modes in this system. Our results reveal exotic phenomena arising from imbalanced pairing and establish a platform for exploring topological superconductivity in non-Hermitian systems.