Vortex Lattice Structure of High Temperature Superconductors.

We study vortex lattice structure of high temperature superconductors by using the Ginzburg–Landau model. The structure of the vortex lattice is oblique at the temperatures well below the transition temperature T[sub c], where the mixed s–d state is expected to have the lowest energy. Whereas, very close to T[sub c], the d[sub x[sup 2]-y[sup 2]] wave is slightly lower in energy, and a triangular vortex lattice recovers. The coexistence and the coupling between the s- and d-waves account for the upward curvature of the upper critical field curve H[sub C2](T). [ABSTRACT FROM AUTHOR]