arXiv subjects

S. M. Quinlan

Publications and source records attributed to S. M. Quinlan.

3 recordsLinked to original sources

arXiv1996

c-Axis Infrared Conductivity of a d_{x^2-y^2}-Wave Superconductor with Impurity and Spin-Fluctuation Scattering

Results of a calculation of the c-axis infrared conductivity sigma_c for a d_{x^2-y^2}-wave superconductor which include both elastic impurity and inelastic spin-fluctuation scattering are presented and compared with the ab-plane conductivity sigma_{ab} in the same model. In this model,the interlayer c-axis coupling is taken to be weak and diffusive. While in clean systems, inelastic scattering leads to a peak at omega = 4*Delta_0 in sigma_{ab} for T < T_c, it has little effect on the corresponding sigma_c, which exhibits structure only at omega = 2*Delta_0 and is directly related to the single-particle density of states N(omega). The c-axis penetration depth lambda_c in the same model is predicted to vary as T^3 at low temperatures in clean samples. We discuss recent optical experiments on the cuprates and compare with these predictions.

supr-con↗

arXiv1995

Infrared conductivity of a d_{x^2-y^2}-wave superconductor with impurity and spin-fluctuation scattering

Calculations are presented of the in-plane far-infrared conductivity of a d_{x^2-y^2}-wave superconductor, incorporating elastic scattering due to impurities and inelastic scattering due to spin fluctuations. The impurity scattering is modeled by short-range potential scattering with arbitrary phase shift, while scattering due to spin fluctuations is calculated within a weak-coupling Hubbard model picture. The conductivity is characterized by a low-temperature residual Drude feature whose height and weight are controlled by impurity scattering, as well as a broad peak centered at 4 Delta_0 arising from clean-limit inelastic processes. Results are in qualitative agreement with experiment despite missing spectral weight at high energies.

cond-mat↗

arXiv1994

Neutron scattering in a d_{x^2-y^2}-wave superconductor with strong impurity scattering and Coulomb correlations

We calculate the spin susceptibility at and below T_c for a d_{x^2-y^2}-wave superconductor with resonant impurity scattering and Coulomb correlations. Both the impurity scattering and the Coulomb correlations act to maintain peaks in the spin susceptibility, as a function of momentum, at the Brillouin zone edge. These peaks would otherwise be suppressed by the superconducting gap. The predicted amount of suppression of the spin susceptibility in the superconducting state compared to the normal state is in qualitative agreement with results from recent magnetic neutron scattering experiments on La_{1.86}Sr_{0.14}CuO_4 for momentum values at the zone edge and along the zone diagonal. The predicted peak widths in the superconducting state, however, are narrower than those in the normal state, a narrowing which has not been observed experimentally.

cond-mat↗