Computational modelling of high temperature superconductors

We are performing Monte-Carlo and Molecular Dynamics simulations of the vortex state in high temperature superconductors using parallel computers. The model for these highly anisotropic cuprate materials consists of a stack of two-dimensional layers in which point-like vortex pancakes interact with each other. Both in-plane vortex-vortex and multi-layer three/four body interactions are included. By varying the temperature and imposed field we study the fundamental behaviour of the vortex lines in the material. We also investigate the effects of pinning centres, which correspond to oxygen vacancies. Our overall aim is to determine the phase diagram of the superconductor numerically and compare this with experimental results