Quantum Monte Carlo Simulation of the Spin 1/2<i>XXZ</i>Model on the Square Lattice

Abstract

We systematically study the spin 1/2 quantum XXZ model on the square lattice using a quantum Monte Carlo method. The temperature dependence of the energy, specific heat and order parameter is calculated for the systems of sizes up to 16×16. Investigating the size dependence carefully, we exarnine the ground-state energy and the existence of the long-range order.