Bosonic integer quantum Hall states in topological bands with Chern number two

TL;DR

This paper demonstrates the emergence of bosonic integer quantum Hall states in topological bands with Chern number two, showing their robustness and phase transitions under various interactions using exact diagonalization.

Contribution

It provides the first detailed numerical evidence of BIQH states in Chern number two bands and explores their stability and phase transitions.

Findings

BIQH state appears at filling factor ν=1 with a quantized Hall conductance of two.

Strong nearest neighbor interactions favor charge density wave formation.

Decreasing onsite interaction leads to a transition from BIQH to superfluid state.

Abstract

We study the interacting bosons in topological Hofstadter bands with Chern number two. Using exact diagonalization, we demonstrate that bosonic integer quantum Hall (BIQH) state emerges at integer boson filling factor $\nu=1$ of the lowest Chern band with evidences including a robust spectrum gap and quantized topological Hall conductance two. Moreover, the robustness of BIQH state against different interactions and next-nearest neighbor hopping is investigated. The strong nearest neighbor interaction would favor a charge density wave. When the onsite interaction decreases, BIQH state undergoes a continuous transition into a superfluid state. Without next-nearest neighbor hopping, the ground state is possibly in a metallic Fermi-liquid-like phase.