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- Tc superconducting materials (cuprates). The properties of high- Tc 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 κ and vortex lattice symmetry. The results are further compared with suitable experimental data on the high- Tc superconducting cuprate YBa2Cu3O7-δ. 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- Tc superconducting cuprates.