Influence of bonding on superconductivity in high-pressure hydrides

TL;DR

This paper explores how modifying bonding characteristics in high-pressure hydrides can potentially enhance their superconducting critical temperatures, using first-principles calculations and hypothetical element interpolation.

Contribution

It introduces a method to optimize superconductivity in hydrides by adjusting bonding via alchemical atom interpolation, revealing pathways to higher critical temperatures.

Findings

Increasing ionic character can raise critical temperatures.

Partial substitution with more electronegative elements improves superconductivity.

The approach offers a new direction for designing high-temperature superconductors.

Abstract

The recent reports on high-temperature superconductivity above 190 K in hydrogen sulfide at 200 GPa pressure, exceeding all previously discovered superconductors, has greatly invigorated the interest in dense hydrogen-rich solids. In this paper, we investigate a possible way to optimize the critical temperature in these compounds using first-principles linear-response calculations. We construct hypothetical alchemical atoms to smoothly interpolate between elements of the chalcogen group and study their bonding and superconducting properties. Our results show that the already remarkable critical temperatures of H$_3$S could be improved even further by increasing the ionic character of the relevant bonds, i.e. replacing sulfur partially with more electronegative elements.