Theory of Andreev reflection in junctions with iron-based High-$T_c$ superconductors

TL;DR

This paper develops a theoretical framework for understanding low-energy quantum transport in junctions involving iron-based high-$T_c$ superconductors, focusing on Andreev reflection and order parameter symmetries.

Contribution

It introduces a comprehensive theory that accounts for surface states and Fermi surface complexity in iron-based superconductors, aiding in identifying their pairing symmetry.

Findings

Identifies signatures of different order parameter symmetries.

Highlights the role of surface states in tunneling spectra.

Provides a tool for experimental determination of pairing symmetry.

Abstract

We construct a theory for low-energy quantum transport in normal$\mid$superconductor junctions involving the recently discovered iron-based high-$T_c$ superconductors. We properly take into account both Andreev bound surface states and the complex Fermi surface topology in our approach, and investigate the signatures of the possible order parameter symmetries for the FeAs-lattice. Our results could be helpful in determining the symmetry of the superconducting state in the iron-pnicitide superconductors.