Magnetic phase transition in the ground-state phase diagram of binary bose gases in optical lattices

¹ Université Côte d'Azur, INPHYNI, CNRS - 06000 Nice, France
² Physics Department, Loyola University New Orleans - 6363 Saint Charles Ave., New Orleans, LA 70118, USA

^(a) laurentdeforgesdeparny@gmail.com (corresponding author)

Received: 16 November 2020
Accepted: 23 March 2021

Abstract

We investigate the ground-state phase diagram of interacting binary Bose gases trapped in two-dimensional optical lattices by means of quantum Monte Carlo simulations. Our simulations reveal a magnetic phase transition from a ferromagnetic-order to a spin insulator inside the Mott insulating phase with two particles per site for quasi-balanced on-site inter- and intra-particle interactions, i.e., . This 3D-XY transition is characterized by the establishment of a finite local magnetic moment along the z-axis, ferromagnetic correlations in the plane and by counterflow superfluidity inside the Mott phase. When decreasing , this transition merges with the Mott-superfluid transition and becomes first order. The merging of the two transitions is investigated with respect to the parameter.