Unconventional Superconductivity in Two-Dimensional Electron Systems with Longe-Range Correlations

TL;DR

This paper investigates how critical antiferromagnetic fluctuations in two-dimensional electron systems lead to unconventional superconductivity characterized by rapidly varying momentum-dependent gap functions and a significant temperature difference between superconducting and spectral gap closures.

Contribution

It reveals the impact of long-range correlations on the momentum space structure of superfluid states and distinguishes between the critical temperatures for superconductivity and spectral gap disappearance.

Findings

Rapidly varying momentum space terms in the mass operator due to correlations

Existence of a temperature range where superconductivity persists without a spectral gap

Significant difference between $T_c$ and $T^*$ in the studied systems

Abstract

Properties of superfluid states of two-dimensional electron systems with critical antiferromagnetic fluctuations are investigated. These correlations are found to result in the emergence of rapidly varying in the momentum space terms in all components of the mass operator, including the gap function $\Delta({\bf p})$. It is shown that a domain, where these terms reside, shrinks with the temperature, leading to a significant difference between the temperature $T_c$, at which superconductivity is terminated, and the temperature $T^*$, where the gap in the single-particle spectrum vanishes.