From superconductivity to non-superconductivity in LiPdH: a first principle approach

TL;DR

This study uses first-principles calculations to investigate LiPdH, revealing that it does not exhibit superconductivity under ambient or high pressure due to weakened electron-phonon interactions.

Contribution

The paper provides a comprehensive first-principles analysis showing LiPdH's lack of superconductivity, contrasting previous theoretical predictions and experimental findings.

Findings

LiPdH does not show superconductivity at ambient pressure.

Increasing pressure suppresses electron-phonon interactions in LiPdH.

No structural phase transition occurs up to 100 GPa.

Abstract

The layered structure of LiPdH was theoretically suggested to be a superconductor as a result of its larger electron-phonon coupling constant compared to that of PdH. However, the experimental results reported contrary findings, with no trace of superconductivity. We study the electronic, vibrational, and superconducting properties of the ambient pressure tetragonal phase of LiPdH ($P4/mmm$) within first principles density functional theory methods, both in the harmonic and anharmonic approximations for the lattice dynamics, and conclude that it does not show any superconducting behavior. High-pressure crystal structure prediction calculations indicate that no structural transition is expected to occur under pressure up to 100 GPa in LiPdH. Our theoretical calculations demonstrate that increasing pressure reduces the density of states at the Fermi surface and consequently weakens electron-phonon interactions, leading to a further suppression of the superconducting critical temperature.