Two-Particle Self-Consistent Approach to Anisotropic Superconductivity

TL;DR

This paper introduces a nonperturbative two-particle self-consistent approach to anisotropic superconductivity, deriving a sum-rule for pairing susceptibility and analyzing the interplay of different pairing symmetries.

Contribution

It develops a novel TPSC-based framework for anisotropic superconductivity, incorporating mode coupling effects and sum-rule constraints.

Findings

Mode coupling suppresses d-wave fluctuations near the Mott insulator.

Derived an exact sum-rule for momentum-dependent pairing susceptibility.

Determined effective pairing interactions consistent with the sum-rule.

Abstract

A nonperturbative approach to anisotropic superconductivity is developed based on the idea of two-particle self-consistent (TPSC) theory by Vilk and Tremblay. A sum-rule which the momentum-dependent pairing susceptibility satisfies is derived. An effective pairing interaction between quasiparticles is determined so that the susceptibility should fulfill this exact sum-rule, in which fluctuations belonging to different symmetries couple at finite momentum. It is demonstrated that the mode coupling between d-wave and s-wave pairing fluctuations leads to suppression of the d-wave fluctuation near the Mott insulator.