Tellurium Hydrides at High Pressures: High-temperature Superconductors

TL;DR

This study predicts high-temperature superconductivity in tellurium hydrides under high pressure, revealing new stable phases with strong electron-phonon coupling and potential for superconductivity above 40 K.

Contribution

It uncovers the stable high-pressure phases of tellurium hydrides and their potential as high-temperature superconductors, expanding the understanding beyond sulfur hydrides.

Findings

Four stable tellurium hydride phases identified above 140 GPa.

H4Te and H5Te2 exhibit ionic structures with exotic units.

Predicted superconducting transition temperatures range from 46 to 104 K.

Abstract

Observation of high-temperature superconductivity in sulfur hydrides at megabar pressures has generated an irresistible wave on searching for new superconductors in other compressed hydrogen-rich compounds. An immediate effort is towards exploration of the relevant candidate of tellurium hydrides, where tellurium is isoelectronic to sulfur but it has a heavier atomic mass and much weaker electronegativity. The hitherto unknown phase diagram of tellurium hydrides at high pressures was investigated by a first-principles swarm structure search. Four energetically stable and metallic stoichiometries of H4Te, H5Te2, HTe and HTe3 were uncovered above 140 GPa, showing a distinct potential energy map of tellurium hydrides from those in sulfur and selenium hydrides. The two hydrogen-rich H4Te and H5Te2 species adopt ionic structures containing exotic quasi-molecular H2 and linear H3 units, respectively. Strong electron-phonon couplings associated with the intermediate-frequency H-derived wagging and bending modes make them good superconductors with high Tc in the range of 46-104 K.