Interaction-driven fractional quantum Hall state of hard-core bosons on kagome lattice at one-third filling

TL;DR

This paper demonstrates that strong interactions in a kagome lattice Bose-Hubbard model can induce a fractional quantum Hall state in bosons, even when the non-interacting band structure is topologically trivial.

Contribution

It reveals an interaction-driven topological phase transition to a fractional quantum Hall state in a system with trivial band topology, identified via advanced numerical methods.

Findings

Groundstate is equivalent to a bosonic fractional quantum Hall Laughlin state

Universal properties include groundstate degeneracy and anyonic statistics

Interaction induces topological order at phase boundary of solid phases

Abstract

There has been a growing interest in realizing topologically nontrivial states of matter in band insulators, where a quantum Hall effect can appear as an intrinsic property of the band structure. While the on-going progress is under way with a number of directions, the possibility of realizing novel interaction-generated topological phases, without the requirement of a nontrivial invariant encoded in single-particle wavefunction or band structure, can significantly extend the class of topological materials and is thus of great importance. Here, we show an interaction-driven topological phase emerging in an extended Bose-Hubbard model on kagome lattice, where the non-interacting band structure is topological trivial with zero Berry curvature in the Brillouin zone. By means of an unbiased state-of-the-art density-matrix renormalization group technique, we identify that the groundstate in a broad parameter region is equivalent to a bosonic fractional quantum Hall Laughlin state, based on the characterization of universal properties including groundstate degeneracy, edge excitations and anyonic quasiparticle statistics. Our work paves a way of finding interaction induced topological phase at the phase boundary of conventionally ordered solid phases.