Topological phases in pseudospin-1 Fermi gases with two-dimensional spin-orbit coupling

TL;DR

This paper proposes a scheme to realize two-dimensional spin-orbit coupling in spin-1 Fermi gases, revealing rich topological phases like triply-degenerate points, quadratic band touchings, and high Chern number superfluids, advancing quantum matter engineering.

Contribution

It introduces a novel experimental scheme for 2D Dresselhaus-type SO coupling in spin-1 Fermi gases, enabling exploration of diverse topological phases without relying on lattice symmetries.

Findings

Prediction of topological phases including triply-degenerate points and triple-Weyl fermions

Identification of a large Chern number (C=5) superfluid with 5 Majorana modes

Proposal for generalizing the scheme to larger spins for quantum matter engineering

Abstract

The recent experimental realization of spin-orbit (SO) coupling for ultracold bosons and fermions opens an exciting avenue for engineering quantum matter that may be challenging to realize in solid state materials such as SO coupled spin-1 fermions. While one-dimensional SO coupling for spin-1 bosons has been experimentally realized, the generation of two-dimensional (2D) SO coupling and its topological properties are largely unexplored. Here we propose an experimental scheme for realizing a 2D Dresselhaus-type SO coupling in a square lattice for spin-1 Fermi gases. Because of the extended spin degree of freedom, many interesting topological phases could exist without relying on lattice point group symmetries that are crucial in solid state materials. These exotic phases include triply-degenerate points, quadratic band touching, a large Chern number ($C=5$) superfluid with 5 Majorana modes, triple-Weyl fermions, etc. Our scheme can be generalized to larger spins and provides a new route for engineering topological quantum matter by utilizing large spin degrees of freedom, instead of specific lattice symmetries.