Anomalous Nernst Effect In Superconducting Vortex

In this dissertation, using two-dimensional XY model, we have studied the Nernst effect and the Ratchet effect in Josephson junction arrays.Using direct current driving force we study numerically the ratchet effect in a two-dimensional Josephson junction array under the fluctuating twist boundary condition. The voltage of system versus density of flux curves showed that voltage has minimal value and superconductive vortexes have regular distributions in these minimal values for homogeneous system. And under the ratchet potential, we found that the voltage of system was suppressed in Josephson junction arrays, this property could be used to modulate the superconductive vortex in the two-dimensional Josephson junction array.We calculate the Nernst signal in the two-dimensional Josephson junction arrays, using the time-dependent Gintzburg-Landau dynamics. The Nernst signal as a function of the temperature and external fields are obtained through extensive simulations. The result shows huge Nernst signal above the superconducting transition temperature. Moreover, a non-monotonous behavior of Nernst signal with respect to the magnetic field is clearly demonstrated. Our findings are qualitatively consistent with the experimental observations in some high-Tc cuprates. Key words:Superconductor; Vortex; Josephson junction arrays; Nernst effect; Ratchet effect...