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

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 x-y 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., U-up arrow down arrow less than or similar to U. This 3D-XY transition is characterized by the establishment of a finite local magnetic moment along the z-axis, ferromagnetic correlations in the x-y plane and by counterflow superfluidity inside the Mott phase. When decreasing U-up arrow down arrow/U, this transition merges with the Mott-superfluid transition and becomes first order. The merging of the two transitions is investigated with respect to the U-up arrow down arrow/U parameter. Copyright (C) 2021 EPLA

Automated summary

In this study, the ground-state phase diagram of interacting binary Bose gases trapped in two-dimensional optical lattices is investigated using quantum Monte Carlo simulations. The simulations reveal a magnetic phase transition from a x-y ferromagnetic order to a spin insulator inside the Mott insulating phase. The merging of this transition with the Mott-superfluid transition is also explored.