Quantum Monte Carlo Study of Pairing Symmetry and Correlation in Iron-based Superconductors

TL;DR

This study uses quantum Monte Carlo simulations to analyze pairing symmetry and electron correlations in iron-based superconductors, revealing that strong electron-electron interactions favor s-wave pairing and likely drive superconductivity.

Contribution

It provides the first systematic non-biased quantum Monte Carlo analysis of pairing mechanisms in a realistic microscopic model for iron-based superconductors.

Findings

s-wave pairing dominates at low temperatures

pairing susceptibility increases with Coulomb interaction

electron correlations are crucial for superconductivity

Abstract

We perform a systematic quantum Monte Carlo study of the pairing correlation in the $S_4$ symmetric microscopic model for iron-based superconductors. It is found that the pairing with an extensive s-wave symmetry robustly dominates over other pairings at low temperature in reasonable parameter region. The pairing susceptibility, the effective pairing interaction and the $(\pi,0)$antiferromagnetic correlation strongly increase as the on-site Coulomb interaction increases, indicating the importance of the effect of electron-electron correlation. Our non-biased numerical results provide a unified understanding of superconducting mechanism in iron-pnictides and iron-chalcogenides and demonstrate that the superconductivity is driven by strong electron-electron correlation effects.