Orbital analogue of quantum anomalous Hall effect in $p$-band systems

TL;DR

This paper explores topological insulators in $p$-band optical lattices induced by orbital angular momentum polarization, revealing a quantum anomalous Hall effect analogue without Landau levels, and discusses potential experimental realization.

Contribution

It introduces a novel mechanism for topological states in $p$-band systems via onsite orbital polarization and connects it to the Haldane model at high rotation speeds.

Findings

Presence of gapless edge modes in the system.

Reduction to Haldane's quantum Hall model at high rotation.

Calculated Berry curvature and quantized Chern numbers.

Abstract

We investigate the topological insulating states of the $p$-band systems in optical lattices induced by the onsite orbital angular momentum polarization, which exhibit gapless edge modes in the absence of Landau levels. This effect arises from the energy level splitting between the onsite $p_x+ip_y$ and $p_x-ip_y$ orbitals by rotating each optical lattice site around its own center. At large rotation angular velocities, this model naturally reduces to two copies of Haldane's quantum Hall model without Landau levels. The distribution of Berry curvature in the momentum space and the quantized Chern numbers are calculated. The experimental realization is also discussed.