Pairing state symmetries of high-Tc superconductors: a comparative study using two Ginzburg-Landau models

An attempt has been made to resolve the issue regarding the pairing symmetry of high-T-c superconducting materials (cuprates). The properties of high-T-c superconductors, which are the signatures of the pairing symmetry of these materials, are being calculated by using the anisotropic s-wave Ginzburg-Landau (GL) theory, i.e. the anisotropic single-order parameter GL theory (ASGL), and is compared with those calculated in a recent work (Karmakar and Dey 2008 J. Phys.: Condens. Matter 20 255218) by the isotropic d-wave GL theory involving mixed symmetry states of the order parameters, i.e. the isotropic two-order parameter GL theory (TIGL), over the entire range of applied magnetic field and temperature for arbitrary values of the GL parameter. and vortex lattice symmetry. The results are further compared with suitable experimental data on the high-T-c superconducting cuprate YBa2Cu3O7-delta. It has been found that the TIGL model definitely gives a better match with the experimental data and is thus more suitable to describe the pairing state symmetries of the high-T-c superconducting cuprates.