Random Interactions

A failed superconductor in a model with random interactions

by Dr. Darshan G Joshi (Harvard University, USA)

Thursday, January 13, 2022 from to (Asia/Kolkata)
at Zoom
Experiments on disordered two-dimensional systems have reported the presence of an anomalous metal phase in the proximity of superconductivity. This phase, dubbed as a failed superconductor, is characterized by a weakly temperature-dependent conductivity (in the low-temperature limit) which is much higher than that of a disordered Fermi liquid metal. We propose a model of interacting electrons with a random and all-to-all electron hopping, Cooper-pair hopping, and exchange interaction. This model hosts a critical anomalous phase/point between a superconductor and a disordered Fermi liquid. In particular, we find a critical Bose metal solution that could be a likely candidate for a failed superconductor. We show that this phase has an enhanced residual conductivity owing to the transport by incoherent Cooper pairs. Further, we report exact results for critical exponents which could be observed in spectroscopic experiments. The critical metallic solutions of this model are similar to those found in Sachdev-Ye-Kitaev (SYK) models.