Phase diagram in the t₂–U space with T=0.05. The red line is the phase boundary between the paramagnetic phase and the antiferromagnetic phase. The black line indicates the Mott transition (dashed line for first-order transitions and solid line for continuous ones). These two kinds of transitions divide the phase diagram to regions corresponding to paramagnetic metal (PM), antiferromagnetic metal (AFM), antiferromagnetic insulator (AFI), and paramagnetic insulator (PI) phases. The red star marks the critical point of the magnetic transition of the Heisenberg limit ( U → ∞ ) obtained by previous studies.^[26] It can be seen that our calculation agrees with it well.