Contrasts in electron correlations and inelastic scattering between LiFeAs and LiFeP revealed by charge transport

TL;DR

This study compares the charge transport and electron correlations in LiFeAs and LiFeP superconductors, revealing significant differences in inelastic scattering and correlation strength that relate to their superconducting properties.

Contribution

It provides a quantitative comparison of transport properties and electron correlations between LiFeAs and LiFeP, highlighting band-dependent scattering differences.

Findings

LiFeP has weaker electron correlations than LiFeAs.

In LiFeP, electron carriers show stronger temperature dependence of scattering than holes.

Differences in scattering may relate to contrasting superconducting gap structures.

Abstract

By using high-quality single crystals, we quantitatively compare the transport properties between LiFeAs and LiFeP superconductors with compensated electron and hole carriers. The low-temperature resistivity follows the Fermi-liquid $AT^2$ dependence with a factor of $\sim 3$ difference in the coefficient $A$. This highlights weaker electron correlations in LiFeP, which is consistent with its $\sim 70$ times lower upper critical field than that of LiFeAs. Our analysis of the magneto-transport data indicates that in LiFeP the electron carriers with lighter masses exhibit stronger temperature dependence of inelastic scattering rate than the holes, which is the opposite to the LiFeAs case. This stark difference in the band-dependent inelastic scattering may be relevant to the recently reported contrasting superconducting gap structures in these two superconductors.