44 research outputs found
Superconducting Fluctuation and Pseudogap in Disordered Short Coherence Length Superconductor
We investigate the role of disorder on the superconducting (SC) fluctuation
in short coherence length d-wave superconductors. The particular intetest is
focused on the disorder-induced microscopic inhomogeneity of SC fluctuation and
its effect on the pseudogap phenomena. We formulate the self-consistent 1-loop
order theory for the SC fluctuation in inhomogeneous systems and analyze the
disordered -- model. The SC correlation function, electronic DOS and
the critical temperature are estimated. The SC fluctuation is localized like a
nanoscale granular structure when the coherence length is short, namely the
transition temperature is high. This is contrasted to the long coherence length
superconductors where the order parameter is almost uniform in the microscopic
scale. In the former case, the SC fluctuation is enhanced by the disorder in
contrast to the Abrikosov-Gorkov theory. These results are consistent with the
STM, NMR and transport measurements in high- cuprates and illuminate
the essential role of the microscopic inhomogeneity. We calculate the spacial
dependence of DOS around the single impurity and discuss the consistency with
the NMR measurements