Wavefunction approach to the fractional anomalous Hall crystal

TL;DR

This paper introduces fractional anomalous Hall crystals (FAHCs) as novel ground states in strongly interacting electron systems with Berry curvature, using variational wavefunctions and energy calculations to compare their stability.

Contribution

It develops a unified variational wavefunction framework for FAHCs and analyzes their energetic favorability over other states in the presence of Berry curvature.

Findings

FAHCs can be energetically favorable with strong interactions.

FAHCs compete with Wigner crystals and integer anomalous Hall crystals.

The study provides semi-analytical energy calculations in the thermodynamic limit.

Abstract

We propose fractional anomalous Hall crystals (FAHCs) as possible ground states of strongly interacting electrons in parent bands with Berry curvature. FAHCs are exotic states of matter that spontaneously break continuous translation symmetry to form a fractional Chern insulator. We construct a unified family of variational wavefunctions that describe FAHCs and their competing states in the presence of uniform parent Berry curvature. We calculate their variational energy with Coulomb interactions semi-analytically in the thermodynamic limit. Our analysis reveals that FAHCs can be energetically favorable over both Wigner crystals and integer anomalous Hall crystals for sufficiently strong interactions or flat dispersion.