Thermodynamic properties of 3D plaquette antiferromagnet

We design a 3D checker-board J-Q model to capture phase transitions between a plaquette-singlet solid with lattice translational symmetry breaking to a 3D Neel phase with spin rotational symmetry breaking. The system is investigated via unbiased large-scale quantum Monte Carlo simulation. We use Binder cumulant to determine the finite temperature phase boundary and measure the specific heat and magnetic susceptibility to reveal the nature of the different phases and their transitions. Our results are closely related with the on-going experimental effort in pressure-induced magnetic phase transitions in Shastry- Sutherland (SS) compound SrCu₂（BO₃）₂