by
Pratap Raychaudhuri(Tata Institute of Fundamental Research, Mumbai, India)
→
Europe/Rome
Aula Conversi (Dip. di Fisica - Edificio G. Marconi)
Aula Conversi
Dip. di Fisica - Edificio G. Marconi
Description
The discovery of high temperature superconducting cuprates and the unusual properties associated with these materials posed the first serious challenge to our conventional understanding of superconductivity based on Bardeen-Cooper-Schrieffer theory. The most striking feature in these materials was the observation of a “pseudogap state” where a gap in the electronic density of states was seen to persist up to temperatures well above the temperature where superconductivity was destroyed. The low carrier density in these materials and the proximity to antiferromagnetic Mott insulating state was largely thought to be responsible for these unusual properties.
Now, experiments performed over the last one decade on a variety of disordered conventional superconductors suggest that the origin unusual properties may be much more general than originally conjectured. In this talk, I will give an overview of experimental investigations on strongly disordered s-wave superconductors which reveal several properties initially thought to be specific to cuprates. I will show how the phase degree of freedom, normally considered irrelevant in clean bulk superconductors, start playing a crucial role in determining the properties of the superconducting state as the superfluid density is reduced in the presence of disorder, giving rise to unusual properties both in the superconducting state and in the normal state above the superconducting transition temperature.
