Vortex-dynamics approach to the Nernst effect in extreme type-II superconductors dominated by phase fluctuations

We present a method to study the Nernst effect and diamagnetism of an extreme type-II superconductor dominated by phase fluctuations. We work directly with vortex variables and our method allows us to tune vortex parameters (e.g., core energy and number of vortex species). We find that diamagnetic response and transverse thermoelectric conductivity (αxy) persist well above the Kosterlitz-Thouless transition temperature, and become more pronounced as the vortex core energy is increased. However, they weaken as the number of internal vortex states is increased. We find that αxy closely tracks the magnetization (-M/T) over a wide range of parameters.