Quantum anomalous Hall states in the $p$-orbital honeycomb optical lattices

TL;DR

This paper proposes a method to realize quantum anomalous Hall states in $p$-orbital honeycomb optical lattices loaded with fermions, demonstrating topologically non-trivial band structures and quantized Hall conductance under experimental conditions.

Contribution

It introduces a novel approach to induce quantum anomalous Hall states in cold atom systems using lattice rotation, expanding possibilities beyond condensed matter realizations.

Findings

Topologically non-trivial band structures achieved via lattice rotation.

Quantized Hall conductance observed in insulating regions.

Robustness of quantum anomalous Hall effects at low temperatures.

Abstract

We study the quantum anomalous Hall states in the $p$-orbital bands of the honeycomb optical lattices loaded with the single component fermions. Such an effect has not been realized in both condensed matter and cold atom systems yet. By applying the available experimental technique developed by Gemelke \textit{et al.} to rotate each lattice site around its own center, the band structures become topologically non-trivial. At a certain rotation angular velocity $\Omega$, a flat band structure appears with localized eigenstates carrying chiral current moments. With imposing the soft confining potential, the density profile exhibits a wedding-cake shaped distribution with insulating plateaus at commensurate fillings. Moreover, the inhomogeneous confining potential induces dissipationless circulation currents whose magnitudes and chiralities vary with the distance from the trap center. In the insulating regions the Hall conductances are quantized, and in the metallic regions the directions and magnitudes of chiral currents cannot be described by the usual local-density-approximation. The quantum anomalous Hall effects are robust at temperature scales small compared to band gaps, which increases the feasibility of experimental realizations.