Study on the critical properties of thin magnetic films using the clock model

Abstract

We study the critical behaviour of very thin magnetic films. This system can be described by the q-state clock model. In order to determine the critical exponents of the system when there exists the Berezinskii-Kosterlitz-Thouless phase between the two phase transitions, we introduce a new technique for calculating the order parameter. The simulation is performed by very high-resolution Monte Carlo method with including the Wang-Landau algorithm. The results showed that the Berezinskii-Kosterlitz-Thouless phase starts to occur when q-3 with a small symmetry breaking field. We obtained not only the critical exponents of a common transition at high temperature but also the ones of unclear transition at low temperature.