Magnetic phases of two-component ultracold bosons in an optical lattice

TL;DR

This paper explores the magnetic phases of two-component ultracold bosons in optical lattices, revealing a rich phase diagram with tunable magnetic order, supersolid phases, and detailed finite-temperature phase diagrams for specific atomic mixtures.

Contribution

It provides the first detailed phase diagrams of magnetic and supersolid phases in two-component ultracold bosons using Dynamical Mean-Field Theory, including finite-temperature effects.

Findings

Discovery of a tunable ferromagnetic to antiferromagnetic transition.

Identification of a supersolid phase with coexisting superfluidity and magnetic order.

Finite-temperature phase diagrams for 87Rb - 41K mixture.

Abstract

We investigate spin-order of ultracold bosons in an optical lattice by means of Dynamical Mean-Field Theory. A rich phase diagram with anisotropic magnetic order is found, both for the ground state and at finite temperatures. Within the Mott insulator, a ferromagnetic to antiferromagnetic transition can be tuned using a spin-dependent optical lattice. In addition we find a supersolid phase, in which superfluidity coexists with antiferromagnetic spin order. We present detailed phase diagrams at finite temperature for the experimentally realized heteronuclear 87Rb - 41K mixture in a three-dimensional optical lattice.