Coupled Ferromagnetic and Nematic Ordering of Fermions in an Optical Flux Lattice

TL;DR

This paper explores how ultracold fermionic atoms in optical flux lattices exhibit coupled ferromagnetic and nematic order due to momentum-dependent interactions and flat bands, revealing accessible magnetic phases with current technology.

Contribution

It demonstrates the emergence of coupled ferromagnetic and nematic order in fermions within optical flux lattices, highlighting the role of momentum-dependent interactions and flat bands.

Findings

Weak repulsive interactions induce magnetic order.

Coupled ferromagnetic and nematic phases are observed.

Accessible with current ultracold atom experiments.

Abstract

Ultracold atoms in Raman-dressed optical lattices allow for effective momentum-dependent interactions among single-species fermions originating from short-range s-wave interactions. These dressed-state interactions combined with very flat bands encountered in the recently introduced optical flux lattices push the Stoner instability towards weaker repulsive interactions, making it accessible with current experiments. As a consequence of the coupling between spin and orbital degrees of freedom, the magnetic phase features Ising nematic order.