Influence of hydrogen on electron-phonon coupling and intrinsic electrical resistivity in zirconium: a first-principles study

TL;DR

This study uses first-principles calculations to explore how hydrogen affects electron-phonon interactions and electrical resistivity in zirconium, revealing a phase transition that reduces resistivity at high hydrogen levels.

Contribution

It provides the first detailed analysis of hydrogen's impact on electron-phonon coupling and resistivity in zirconium, linking phase transition to resistivity decrease.

Findings

Resistivity decreases at high hydrogen concentrations (>1.5 H/Zr).

Phase transition induces lattice distortion that reduces electron-phonon coupling.

Elimination of imaginary phonon frequencies correlates with resistivity reduction.

Abstract

The paper presents the first-principle calculation of the electron-phonon coupling and the temperature dependence of the intrinsic electrical resistivity of the zirconium-hydrogen system with various hydrogen concentrations. The nature of the anomalous decrease in the electrical resistivity of the Zr-H system with the increase of hydrogen concentration (at the high concentrations of H/Zr$>$1.5) was studied. It was found that the hydrogen concentration, where the resistivity starts to decrease, is very close to the critical concentration of the $\delta-\varepsilon$ phase transition. It was shown that the tetragonal lattice distortion due to the $\delta-\varepsilon$ phase transition of the Zr-H system eliminates imaginary phonon frequencies and the strong electron-phonon coupling of the $\delta$ phase and, as a result, leads to the reduction of the electrical resistivity of the Zr-H system at a high hydrogen concentration.