Opposite impact of thermal expansion and phonon anharmonicity on the phonon-limited resistivity of elemental metals from first principles

TL;DR

This paper investigates how thermal expansion and phonon anharmonicity differently influence the electrical resistivity of elemental metals, emphasizing the importance of including both effects for accurate first-principles predictions.

Contribution

It introduces a comprehensive first-principles approach that explicitly accounts for both thermal expansion and phonon anharmonicity in calculating metal resistivity.

Findings

Thermal expansion increases electron-phonon coupling and resistivity.

Phonon anharmonicity decreases resistivity.

Including both effects yields more accurate resistivity predictions for Pb, Nb, and Al.

Abstract

Understanding electrical resistivity in metals remains a central challenge in quantifying charge transport at finite temperature. Current first-principles calculations based on the Boltzmann transport equation often match experiments, yet they almost always neglect the effect of thermal expansion and phonon anharmonicity. We show that both effects exert an opposite impact on electron-phonon coupling and on electrical resistivity. Thermal expansion enhances the coupling and leads to overestimation of resistivity, whereas anharmonic effects reduce it. By explicitly incorporating both effects, we establish a more complete description of resistivity in elemental metals, demonstrated here for Pb, Nb, and Al.