First Order Topological Phase Transitions and Disorder Induced Majorana Modes in Interacting Fermion Chains

TL;DR

This paper investigates first order topological phase transitions in interacting fermion chains, revealing how disorder can induce Majorana modes and phase coexistence, using mean-field and DMRG methods.

Contribution

It introduces a combined mean-field and DMRG approach to identify first order topological transitions and demonstrates disorder-induced Majorana modes in fermion chains.

Findings

First order topological transitions between superconducting and insulating phases.

Disorder induces phase coexistence and generates Majorana particles.

Topological phases characterized by winding numbers and entanglement spectra.

Abstract

Using a combination of the mean-field Bogoliubov deGennes (BdG) approach and the Density Matrix Renormalization Group (DMRG) method, we discover first order topological transitions between topological superconducting and trivial insulating phases in a sawtooth lattice of inter-site attractive fermions. Topological characterization of different phases is achieved in terms of winding numbers, Majorana edge modes and entanglement spectra. By studying the effect of disorder on the first order topological phase transitions, we establish the disorder-induced topological phase coexistence as a mechanism for generating a finite density of Majorana particles.