Monte Carlo Renormalization Group Study of the Heisenberg and the XY Antiferromagnet on the Stacked Triangular Lattice and the Chiral φ⁴ Model

抄録

With the help of the improved Monte Carlo renormalization-group scheme, we numerically investigate the renormalization group flow of the antiferromagnetic Heisenberg and XY spin model on the stacked triangular lattice (STA-model) and its effective Hamiltonian, 2N-component chiral φ⁴ model which is used in the field-theoretical studies. We find that the XY-STA model with lattice size 126×144×126 exhibits clear first-order behavior. We also find that the renormalization-group flow of the STA model is well reproduced by the chiral φ⁴ model, and that there are no chiral fixed points of renormalization-group flow for N=2 and 3 cases. This result indicates that the Heisenberg-STA model also undergoes first-order transition.