Topological order in the Kitaev/Majorana chain in the presence of disorder and interactions

TL;DR

This paper investigates how interactions and disorder influence topological order in a one-dimensional Kitaev/Majorana chain, revealing that moderate levels can stabilize the phase while strong disorder suppresses it.

Contribution

It provides a detailed phase diagram of the Kitaev chain with interactions and disorder using DMRG, highlighting the conditions under which topological order is stabilized or suppressed.

Findings

Moderate disorder or interactions stabilize topological order.

Strong disorder suppresses topological phase.

Interactions have a dual role depending on disorder strength.

Abstract

We study the combined effect of interactions and disorder on topological order in one dimension. To this end we consider a generalized Kitaev chain including fermion-fermion interactions and disorder in the chemical potential. We determine the phase diagram by performing density-matrix renormalization group calculations on the corresponding spin-1/2 chain. We find that moderate disorder or repulsive interactions individually stabilize the topological order, which remains valid for their combined effect. However, both repulsive and attractive interactions lead to a suppression of the topological phase at strong disorder.