Proposed realization of itinerant ferromagnetism in optical lattices

TL;DR

This paper proposes a method to realize itinerant ferromagnetism in cold fermionic atoms within optical lattices, leveraging flat band effects in a honeycomb lattice to enhance interactions and enable experimental observation.

Contribution

It introduces a novel scheme to achieve itinerant ferromagnetism in optical lattices using p-orbital bands and flat band effects, avoiding decay issues near Feshbach resonances.

Findings

Interaction-driven ferromagnetic transition in p-orbital bands.

Enhanced stability without decay to molecular states.

Potential experimental detection methods discussed.

Abstract

We propose to realize the itinerant ferromagnetism of two-component cold fermionic atoms in the $p$-orbital bands in optical lattices. The band flatness in the two-dimensional honeycomb lattice dramatically amplifies the interaction effect driving the ferromagnetic transition even with a relatively weak repulsive interaction. This scheme has the advantage that the stability of the system can be maintained without suffering decaying to the molecular state as one approaches the Feshbach resonance from the side with positive scattering length. Experimental signatures and detections are also discussed.