Electronic Behavior of Superconducting SmFeAsO0.75

TL;DR

This study investigates the electronic properties of superconducting SmFeAsO0.75, revealing a small superconducting jump, a temperature-dependent Hall coefficient, and evidence of a pseudogap, contributing to understanding iron-based superconductor behavior.

Contribution

It provides systematic transport and heat capacity measurements of SmFeAsO0.75, highlighting deviations from BCS theory and evidence of a pseudogap in this iron-based superconductor.

Findings

Small normalized superconducting jump compared to BCS predictions

Strong temperature dependence of the Hall coefficient

Evidence of a pseudogap up to 160 K

Abstract

High-quality polycrystalline SmFeAsO0.75 was synthesized with a superconducting transition width less than 1 K, and the electronic behavior was systematically studied by transport and specific heat measurements. An obvious superconducting jump was witnessed, together with a very small normalized superconducting jump, which is much smaller than expected by the BCS theory. A strong temperature dependent Hall coefficient was found and attributed to the partial gapping of the Fermi surface up to the temperature of 160 K which was predicted and supported by the emergence of the pseudogap. The charge-carrier density as well as the effective mass were also obtained and discussed in detail.