Lara Benfatto

Quantum and classical phase fluctuations in 2D superconductors

In the last few years an increasing experimental evidence has been accumulating that in low-dimensional superconductors the superconducting ground state develops an emergent inhomogeneity. This behaviour can be triggered by strong disorder, as it has been seen in conventional superconductors like NbN, InOx and TiN, but it can be also induced by quantum confinement at the nanoscale, as it happens in arrays made of Al nanograins or in the 2D electron gas at the interface of insulating LAO/STO oxides.

A crucial question is the understanding how the superconducting phase modes adapt to this fragmented background, and what are their experimental signatures in transport and spectroscopic probes. In this talk I will review our theoretical progresses in the understanding of quantum and classical disordered phase fluctuations in quasi-2D superconductors. In particular I will focus on the extra absorption of quantum phase mode at low temperatures, and on the fate of the Berezinskii-Kosterlitz-Thouless transition near Tc.