Competitions of magnetism and superconductivity in FeAs-based materials

TL;DR

This paper investigates the interplay between magnetism and superconductivity in FeAs-based materials using a two-orbital model and numerical Hartree-Fock calculations, revealing competing phases and coexistence regions.

Contribution

It introduces a detailed numerical study of the ground state phases in FeAs-based superconductors, highlighting the coexistence and competition of magnetic and superconducting orders.

Findings

Competition between spin-density wave and superconductivity with doping

Possible coexistence of magnetism and superconductivity in a small doping region

Superconducting pairing is spin singlet, orbital even, with mixed s$_{xy}$ + d$_{x^{2}-y^{2}}$ wave symmetry

Abstract

Using the numerical unrestricted Hartree-Fock approach, we study the ground state of a two-orbital model describing newly discovered FeAs-based superconductors. We observe the competition of a $(0, \pi)$ mode spin-density wave and the superconductivity as the doping concentration changes. There might be a small region in the electron-doping side where the magnetism and superconductivity coexist. The superconducting pairing is found to be spin singlet, orbital even, and mixed s$_{xy}$ + d$_{x^{2}-y^{2}}$ wave (even parity).