Charge fluctuations and topological phases in Kitaev-Heisenberg ladders

TL;DR

This study examines how charge fluctuations and doping affect the stability of topological phases in Kitaev-Heisenberg ladders, revealing the conditions under which topological order persists or vanishes.

Contribution

It provides a detailed analysis of the interplay between charge fluctuations, magnetic order, and topological phases using DMRG in doped Kitaev-Heisenberg ladders.

Findings

Increasing electron bandwidth suppresses topological phases.

Critical hopping values where string order vanishes are identified.

Charge fluctuations influence the stability of topological order.

Abstract

We investigate the stability of topological phases in doped Kitaev-Heisenberg ladders by studying the competition with itinerant electrons and the associated charge fluctuations in a Hubbard model on a honeycomb ribbon geometry. We analyze the evolution of string order parameters, spin correlations, and charge fluctuations as functions of hopping amplitude and interaction strength in a half-filled band. Our results from density matrix renormalization group (DMRG) calculations show that increasing electron bandwidth progressively suppresses the topological phases, shifting and narrowing their stability regions in the phase diagram. We identify the critical values of hopping where string order vanishes and characterize the interplay between magnetic order and charge fluctuations. These findings provide insight into the robustness of topological phases against doping and charge dynamics, with implications for candidate Kitaev materials and engineered quantum systems.