Field-induced topological pair-density wave states in a multilayer optical lattice

TL;DR

This paper explores how Zeeman fields and spin-orbit coupling induce topological pair-density wave states in multilayer optical lattices, revealing complex superfluid phases with distinct layer properties and topological characteristics.

Contribution

It introduces a novel mechanism for topological PDW phases in multilayer systems driven by Zeeman and spin-orbit interactions, with detailed topological analysis.

Findings

Identification of layer-dependent superfluid order parameters

Emergence of topological PDW phases with nontrivial Chern numbers

Mechanistic understanding of phase formation in multilayer systems

Abstract

We study the superfluid phases of a Fermi gas in a multilayer optical lattice system in the presence of out-of-plane Zeeman field, as well as spin-orbit (SO) coupling. We show that the Zeeman field combined with the SO coupling leads to exotic topological pair-density wave (PDW) phases in which different layers possess different superfluid order parameters, even though each layer experiences the same Zeeman field and the SO coupling. We elucidate the mechanism of the emerging PDW phases, and characterize their topological properties by calculating the associated Chern numbers.