Quantum Monte Carlo simulation of thin magnetic films

TL;DR

This paper employs quantum Monte Carlo simulations to analyze the magnetic properties of thin ferromagnetic films, providing unbiased results that validate and compare with existing theoretical approaches, and demonstrating the method's broad applicability.

Contribution

It applies the stochastic series expansion quantum Monte Carlo method to thin magnetic films with local anisotropies, offering an unbiased benchmark against approximate theories.

Findings

Magnetization curves are calculated and compared with other methods.

The Monte Carlo results serve as an unbiased check of theoretical approximations.

The study demonstrates the versatility of the cluster-loop formulation for quantum spin models.

Abstract

The stochastic series expansion quantum Monte Carlo method is used to study thin ferromagnetic films, described by a Heisenberg model including local anisotropies. The magnetization curve is calculated, and the results compared to Schwinger boson and many-body Green's function calculations. A transverse field is introduced in order to study the reorientation effect, in which the magnetization changes from out-of-plane to in-plane. Since the approximate theoretical approaches above differ significantly from each other, and the Monte Carlo method is free of systematic errors, the calculation provides an unbiased check of the approximate treatments. By studying quantum spin models with local anisotropies, varying spin size, and a transverse field, we also demonstrate the general applicability of the recent cluster-loop formulation of the stochastic series expansion quantum Monte Carlo method.