Numerical study of p-wave superconductivity in Sr2RuO4

Abstract

This thesis contains detailed numerical studies of the superconducting state of Sr2RuO4. This material's magnetic response displays hc=4e periodicity in multiply connected samples, a striking departure from hc=2e periodicity of the Little-Parks effect. One likely explanation for this is that, instead of the Cooper pairs existing in a spin-singlet state as in most conventional superconductors, the pairs form in an l = 1, or p-wave, angular momentum state. The additional spin degree of freedom offered by this angular momentum state allows the formation of half-quantum vortices possessing half of the usual flux quantum. In Chapter 1, I briefly review p-wave superconductivity and see how it supports half-quantum vortices. In Chapter 2, I review the conventional Ginzburg- Landau formalism for treating superconductivity. We then extend this formalism to treat p-wave superconductivity. In Chapter 3, I discuss the numerical methods used to solve the coupled Ginzburg-Landau-Maxwell equations for the model. In Chapter 4, I present numerical solutions of the Ginzburg-Landau equations for the proposed model in realistic geometries and show that the data can be simulated using physically reasonable parameters. I also analyze an important alternative explanation to the presence of half-flux states involving integer vortices penetrating the walls of the sample. In Chapters 6 and 7, I present analyses of measurements of magnetoresistance oscillations in Sr2RuO4 including evidence of phase-shift due to Abrikosov vortices.