Anisotropic Energy Gaps of Iron-based Superconductivity from Intra-band Quasiparticle Interference in LiFeAs

TL;DR

This study uses intra-band quasiparticle interference techniques to map the anisotropic superconducting energy gaps on different electronic bands in LiFeAs, providing insights into the pairing mechanism in iron-based superconductors.

Contribution

Introduces a novel intra-band QPI method to determine anisotropic energy gaps on multiple bands in LiFeAs, advancing understanding of superconducting pairing mechanisms.

Findings

Identified three hole-like bands: , , and .

Determined the anisotropy, magnitude, and orientation of energy gaps on these bands.

Provides data to support theoretical models of Cooper pairing in iron-based superconductors.

Abstract

If strong electron-electron interactions between neighboring Fe atoms mediate the Cooper pairing in iron-pnictide superconductors, then specific and distinct anisotropic superconducting energy gaps \Delta_i(k) should appear on the different electronic bands i. Here we introduce intra-band Bogoliubov quasiparticle scattering interference (QPI) techniques for determination of \Delta_i(k) in such materials, focusing on LiFeAs. We identify the three hole-like bands assigned previously as \gamma, \alpha_2 and \alpha_1, and we determine the anisotropy, magnitude and relative orientations of their \Delta_i(k). These measurements will advance quantitative theoretical analysis of the mechanism of Cooper pairing in iron-based superconductivity.