Aula Rasetti (Dip. di Fisica - Edificio G. Marconi)
Aula Rasetti
Dip. di Fisica - Edificio G. Marconi
Description
There is growing evidence, from experiments and numerical simulations, that a key feature of sufficiently disordered superconductors is the spatial inhomogeneity of the order parameter. In this talk I present results for two examples where inhomogeneities play an important role: engineered nano-granular materials and disordered superconductors around an Anderson transition characterized by weakly multifractal one-body eigenstates. In the former we show that the global critical temperature can be substantially enhanced in weakly coupled materials such as Al. In the latter we compute the superconducting order parameter analytically, including its energy dependence and statistical distribution in space. The spatial distribution of the order parameter is found to be always log-normal. The global critical temperature, computed by percolation techniques and neglecting phase fluctuations, is enhanced with respect to the clean limit only for very weakly coupled superconductors. Our results are consistent with experiments, where enhancement of the critical temperature is observed in Al thin films, a weakly coupled metallic superconductor, but not in more strongly coupled materials.
