Complexity in granularity with intrinsic superconductivity transition near room temperature

by Vladimir Kresin (LBNL, UC Berkeley)

Tuesday 24 Apr 2012, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dipartiemnto di Fisica - Ed. G. Marconi)

The physical scenario of an optimum inhomogeneity for high temperature superconductivity has been discussed soon after the BCS theory. Here, I will present theoretical and experimental arguments to discuss a scenario based on superconducting “islands”. I call T*, the critical temperature where the pseudo gap appears as the “intrinsic Tc” since it is the temperature at which superconducting “islands” form, indicated by the appearance of diamagnetism. The Tc* can be much larger than Tc and can approach room temperature. A scenario of inhomogeneous superconductivity in small grains at Tc* that proliferate with decreasing temperature up to the point of the formation of the bulk superconducting phase via percolation or Josephson coupling, will be discussed. The origin of the inhomogeneity, weather inhomogeneous charge distribution or non-uniform distribution of pair breakers, will also be treated in with experimental examples.