Probing interaction-induced ferromagnetism in optical superlattices

TL;DR

This paper proposes a controllable method to observe and stabilize interaction-induced ferromagnetism in ultracold fermionic atoms within optical superlattices, using double-exchange processes to maintain ferromagnetic correlations.

Contribution

It introduces a novel approach to induce and stabilize ferromagnetism in optical lattices by mediating long-range correlations through double-exchange mechanisms.

Findings

Proposed a method to observe Nagaoka ferromagnetism in optical superlattices.

Demonstrated that weak interplaquette coupling destroys ferromagnetic correlations.

Suggested techniques for experimental realization and detection of ferromagnetic states.

Abstract

We propose a controllable method for observing interaction induced ferromagnetism in ultracold fermionic atoms loaded in optical superlattices. We first discuss how to probe and control Nagaoka ferromagnetism in an array of isolated plaquettes (four lattice sites arranged in a square). Next, we show that introducing a weak interplaquette coupling destroys the ferromagnetic correlations. To overcome this instability we propose to mediate long-range ferromagnetic correlations among the plaquettes via double-exchange processes. Conditions for experimental realization and techniques to detect such states are discussed.