Vortex Dynamics Based On Time-dependent Ginzburg-Landau Equations

In this thesis, the Ginzburg-Landau theory, which can characterize the property of the mixed state in type-Ⅱ superconductors, has been described briefly. The Ginzburg-Landau equations have been deduced into dimensionless forms and afterwards discretized for the simulation program. The numerical model based on finite difference method has been established, and we investigate the vortex dynamics in2D superconductors by this simulation method. We introduced the method how to aid pinning, temperature and current to the simulation models, so we can simulate the evolution of vortex in different external conditions and get the property of steady state of equilibrium.Firstly, we simulated the vortex distribution in pure square samples. As a result the vortex distributed as the quasi-triangle lattice. We also simulated the vortex distribution with changed field under triangle and conformal pinning. The Ⅰ-Ⅴ curve under different temperature with no pinning when current introduced satisfy the Ohm’s law. The resistance of Magnetic flux flow changed in the same direction with the temperature. The quasi-triangle vortex distribution changed to perfect triangle vortex distribution because of the Lorentz force when the current introduced. We also give some interpretations from qualitative.We calculate the Nernst signal when introduced the temperature gradient based on the computation of Ⅰ-Ⅴ curve. The Nernst signal as a function of the temperature and external fields are obtained through extensive simulations.