Pairing dynamics in strongly correlated superconductivity

TL;DR

This paper uses cellular dynamical mean-field theory to identify the energy scales and retardation effects associated with spin fluctuations in d-wave superconductivity within the 2D Hubbard model, linking these to experimental observations.

Contribution

It demonstrates the role of short-range spin fluctuations in pairing and clarifies the energy scales relevant for superconductivity in the Hubbard model.

Findings

Retardation effects are associated with short-range spin fluctuations.

Superconductivity disappears when low energy antiferromagnetic fluctuations vanish.

The energy scales for pairing vary with interaction strength and doping.

Abstract

Confirmation of the phononic origin of Cooper pair formation in superconductors came with the demonstration that the interaction was retarded and that the corresponding energy scales were associated with phonons. Using cellular dynamical mean-field theory for the two-dimensional Hubbard model, we identify such retardation effects in d-wave pairing and associate the corresponding energy scales with short-range spin fluctuations. We find which frequencies are relevant for pairing as a function of interaction strength and doping and show that the disappearance of superconductivity on the overdoped side coincides with the disappearance of the low energy feature in the antiferromagnetic fluctuations, as observed in neutron scattering experiments.