Simple Real-Space Picture of Nodeless and Nodal s-wave Gap Functions in Iron Pnictide Superconductors

TL;DR

This paper introduces a straightforward orbital-based real-space parameterization of the superconducting gap functions in iron pnictides, capturing both nodeless and nodal s-wave behaviors with simplicity and physical intuition.

Contribution

It presents a novel, simple real-space orbital approach to model the gap functions in iron pnictides, improving interpretability and phenomenological understanding.

Findings

Reproduces microscopic gap structures accurately

Provides an intuitive real-space picture of pairing

Simplifies the treatment of superconducting states

Abstract

We propose a simple way to parameterize the gap function in iron pnictides. The key idea is to use orbital representation, not band representation, and to assume real-space short-range pairing. Our parameterization reproduces fairly well the structure of gap function obtained in microscopic calculation. At the same time the present parameterization is simple enough to obtain an intuitive picture and to develop a phenomenological theory. We also discuss simplification of the treatment of the superconducting state.