Future Study of Dense Superconducting Hydrides at High Pressure

TL;DR

This paper reviews the progress and challenges in understanding high-temperature superconductivity in dense hydrides under high pressure, highlighting theoretical predictions and experimental findings that aim to achieve ambient condition superconductivity.

Contribution

It provides a comprehensive perspective on the current state of hydride superconductivity research, emphasizing the need to resolve controversies between theory and experiment.

Findings

High Tc in hydrides aligns with theoretical predictions.

Discrepancies exist between predicted and observed properties.

Further experiments are needed to clarify the mechanisms.

Abstract

The discovery of a record high superconducting transition temperature (Tc) of 288 K in a pressurized hydride inspires new hope to realize ambient condition superconductivity. Here, we give a perspective on the theoretical and experimental studies of hydride superconductivity. Predictions based on the BCS-Eliashberg-Midgal theory with the aid of density functional theory have been playing a leading role in the research and guiding the experimental realizations. To date, about twenty hydrides experiments have been reported to exhibit high-Tc superconductivity and their Tc agree well with the predicted values. However, there are still some controversies existing between the predictions and experiments, such as no significant transition temperature broadening observed in the magnetic field, the experimental electron-phonon coupling beyond the Eliashberg-Midgal limit, and the energy dependence of density of states around the Fermi level. To investigate these controversies and the origin of the highest Tc in hydrides, key experiments are required to determine the structure, bonding, and vibrational properties associated with H atoms in these hydrides.