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

This paper presents the first-principles 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 high concentrations of H/Zr>1.5) is studied. It is found that the hydrogen concentration where the resistivity starts to decrease is very close to the critical concentration of the δ-ϵ phase transition. It is shown that the tetragonal lattice distortion due to the δ-ϵ phase transition of the Zr-H system eliminates imaginary phonon frequencies and the strong electron-phonon coupling of the δ phase and, as a result, leads to the reduction of the electrical resistivity of the Zr-H system at a high hydrogen concentration.