Pseudogap and Superconducting Fluctuation in High-Tc Cuprates: Theory beyond 1-loop Approximation

TL;DR

This paper investigates the pseudogap phenomena caused by superconducting fluctuations in high-Tc cuprates, using a theoretical approach beyond the 1-loop approximation to better understand their microscopic origins and effects.

Contribution

It introduces a microscopic derivation of superconducting fluctuations beyond the 1-loop approximation within the Hubbard model, emphasizing the role of vertex corrections.

Findings

Vertex corrections significantly affect the single-particle spectral function.

The 1-loop approximation remains valid for certain quantities like spin susceptibility.

Superconducting fluctuations are crucial for understanding the pseudogap phenomena.

Abstract

The pseudogap phenomena induced by the SC fluctuation are investigated in details. We perform a calculation beyond the 1-loop approximation. The SC fluctuation is microscopically derived on the basis of the repulsive Hubbard model. The vertex corrections are collected in the infinite order with use of the quasi-static approximation. The single-particle excitations, NMR 1/T_{1}T, spin susceptibility and superconducting transition temperature are discussed. The important role of the vertex correction is pointed out for the single particle spectral function. On the other hand, the validity of the 1-loop order theory is confirmed for other quantities. We shed light on the essential nature of SC fluctuation leading to the pseudogap from the comparison with spin and charge fluctuations.