High temperature superconductivity in the lanthanide hydrides at extreme pressures

TL;DR

This paper investigates the potential for high-temperature superconductivity in lanthanide hydrides at pressures above 200 GPa, using first principles calculations to analyze their structure, stability, and electron-phonon interactions.

Contribution

It introduces a first principles computational approach including many-body corrections to study ultra-high pressure lanthanide hydrides and their superconducting properties.

Findings

Density functional theory accurately predicts structure and phonon frequencies.

Many-body corrections increase the estimated critical temperature.

Spectral weight transfer of f-states influences superconductivity.

Abstract

Hydrogen-rich superhydrides are promising high-Tc superconductors, with superconductivity experimentally observed near room temperature, as shown in recently discovered lanthanide superhydrides at very high pressures, e.g. LaH10 at 170 GPa and CeH9 at 150 GPa. Superconductivity is believed to be closely related with the high vibrational modes of the bound hydrogen ions. Here we study the limit of extreme pressures (above 200 GPa) where lanthanide hydrides with large hydrogen content have been reported. We focus on LaH16 and CeH16, two prototype candidates for achieving a large electronic contribution from hydrogen in the electron-phonon coupling. In this work, we propose a first principles calculation platform with the inclusion of many-body corrections to evaluate the detailed physical properties of the Ce-H and La-H systems and to understand the structure, stability and superconductivity of these systems at ultra-high pressure. We provide a practical approach to further investigate conventional superconductivity in hydrogen rich superhydrides. We report that density functional theory provides accurate structure and phonon frequencies, but many-body corrections lead to an increase of the critical temperature, that is associated with spectral weight transfer of the f-states.