Mott insulating phases and magnetism of fermions in a double-well optical lattice

TL;DR

This paper explores Mott insulating phases and magnetic orderings of two-component fermions in a double-well optical lattice, revealing tunable magnetic phases with higher Neel temperatures, aiding experimental realization.

Contribution

It introduces a theoretical study of magnetic phases in a double-well optical lattice, showing how to control magnetic ordering and Neel temperature via orbital energy tuning.

Findings

Identification of two types of Mott insulators at two fermions per site.

Demonstration that Neel temperature can be significantly increased.

Control of magnetic phases through orbital energy splitting.

Abstract

We theoretically investigate, using non-perturbative strong correlation techniques, Mott insulating phases and magnetic ordering of two-component fermions in a two-dimensional double-well optical lattice. At filling of two fermions per site, there are two types of Mott insulators, one of which is characterized by spin-1 antiferromagnetism below the Neel temperature. The super-exchange interaction in this system is induced by the interplay between the inter-band interaction and the spin degree of freedom. A great advantage of the double-well optical lattice is that the magnetic quantum phase diagram and the Neel temperature can be easily controlled by tuning the orbital energy splitting of the two-level system. Particularly, the Neel temperature can be one order of magnitude larger than that in standard optical lattices, facilitating the experimental search for magnetic ordering in optical lattice systems.