Modulated Structure Calculated for Superconducting Hydrogen Sulfide

Abstract

Compression of hydrogen sulfide using first principles metadynamics and molecular dynamics calculations revealed a modulated structure with high proton mobility which exhibits a diffraction pattern matching well with experiment. The structure consists of a sublattice of rectangular meandering SH^- chains and molecular-like H₃ S⁺ stacked alternately in tetragonal and cubic slabs forming a long-period modulation. The novel structure offers a new perspective on the possible origin of the superconductivity at very high temperatures in which the conducting electrons in the SH chains are perturbed by the fluxional motions of the H₃ S resulting in strong electron-phonon coupling.

Keywords: density functional theory; high-pressure chemistry; high-temperature superconductivity; hydrogen sulfide; superconductivity.