Abstract

We study the correlated flat-band checkerboard lattice at fractional filling ν = 2/3 using exact diagonalization and density-matrix renormalization group simulations. The global phase diagram includes a robust C = 2/3 fractional quantum anomalous Hall phase surrounded by charge-density-wave phases and a Fermi-liquid regime. A key result is a transition from the fractional quantum anomalous Hall phase into a (π, π) charge-density-wave metal driven by roton condensation, with a soft neutral mode and diverging density fluctuations at the transition.

Abstract

We study the correlated flat-band checkerboard lattice at fractional filling ν = 2/3 using exact diagonalization and density-matrix renormalization group simulations. The global phase diagram includes a robust C = 2/3 fractional quantum anomalous Hall phase surrounded by charge-density-wave phases and a Fermi-liquid regime. A key result is a transition from the fractional quantum anomalous Hall phase into a (π, π) charge-density-wave metal driven by roton condensation, with a soft neutral mode and diverging density fluctuations at the transition.

Abstract

We study the correlated flat-band checkerboard lattice at fractional filling ν = 2/3 using exact diagonalization and density-matrix renormalization group simulations. The global phase diagram includes a robust C = 2/3 fractional quantum anomalous Hall phase surrounded by charge-density-wave phases and a Fermi-liquid regime. A key result is a transition from the fractional quantum anomalous Hall phase into a (π, π) charge-density-wave metal driven by roton condensation, with a soft neutral mode and diverging density fluctuations at the transition.

Abstract

We study the correlated flat-band checkerboard lattice at fractional filling ν = 2/3 using exact diagonalization and density-matrix renormalization group simulations. The global phase diagram includes a robust C = 2/3 fractional quantum anomalous Hall phase surrounded by charge-density-wave phases and a Fermi-liquid regime. A key result is a transition from the fractional quantum anomalous Hall phase into a (π, π) charge-density-wave metal driven by roton condensation, with a soft neutral mode and diverging density fluctuations at the transition.