arXiv:2407.05556 · Physical Review A
Ground-state phase diagram of the SU ( 4 ) Heisenberg model on a plaquette lattice
Ryui Kaneko, Shimpei Goto, Ippei Danshita
Abstract
We investigate the ground state of the $\mathrm{SU}(4)$ Heisenberg model on a square lattice with spatial anisotropy on each plaquette bond using the tensor-network method based on infinite projected entangled pair states. We find that the $\mathrm{SU}(4)$ singlet ground state appears in the strongly anisotropic limit, whereas N\'eel and valence-bond crystal orders coexist in the nearly isotropic limit. By examining the intermediate parameter region, we identify a phase transition between these phases. The nature of the phase transition is likely to be of first order, and the transition point is estimated to be around ${J}^{\ensuremath{'}}/J\ensuremath{\approx}0.85(5)$, where $J$ and ${J}^{\ensuremath{'}}$ are the interaction strengths of intra- and interplaquette bonds, respectively. We also calculate the anisotropy dependence of singlet correlations on a plaquette bond, which will be useful for future experiments of ultracold atoms in optical lattices.