Challenging Magnetic Field Dependence of the Residual Resistivity of the Heavy-Fermion Metal CeCoIn5

TL;DR

This paper explains the unusual magnetic field and pressure dependence of residual resistivity in CeCoIn5 by linking it to a flat electronic band, affecting various thermodynamic and transport properties.

Contribution

It identifies the role of a flat band in CeCoIn5 and explains its influence on residual resistivity and other properties under magnetic field and pressure.

Findings

Suppression of residual resistivity rho_0 under magnetic field and pressure.

Evidence for the presence of a flat band in CeCoIn5.

Impact of flat bands on thermodynamic and transport properties.

Abstract

An explanation of paradoxical behavior of the residual resistivity rho_0 of the heavy-fermion metal CeCoIn5 in magnetic fields and under pressure is developed. The source of this behavior is identified as a flattening of the single-particle spectrum, which exerts profound effects on the specific heat, thermal expansion coefficient, and magnetic susceptibility in the normal state, the specific heat jump at the point of superconducting phase transition, and other properties of strongly correlated electron systems in solids. It is shown that application of a magnetic field or pressure to a system possessing a flat band leads to a strong suppression of rho_0. Analysis of its measured thermodynamic and transport properties yields direct evidence for the presence of a flat band in CeCoIn5.