paper

Pressure-induced decomposition of solid hydrogen sulfide

arXiv:1501.01784 · doi:10.1103/PhysRevB.91.180502

Abstract

Solid hydrogen sulfide is well known as a typical molecular crystal but its stability under pressure is still under debate. Particularly, Eremets et al. found the high pressure superconductivity with $T_{c} \approx$ 190 K in a H $_{2}$ S sample [arXiv: 1412.0460 (2014)] which is associates with the elemental decomposition into H $_{3}$ S [Sci. Rep. 4, 6968 (2014)]. Therefore, on what pressure H $_{2}$ S can decompose and which kind of the products of decomposition urgent need to be solved. In this paper, we have performed an extensive structural study on different stoichiometries H $_{n}$ S with $n > 1$ under high pressure using $ab$ $ini t i o$ calculations. Our results show that H $_{2}$ S is stable below 50 GPa and decomposes into H $_{3}$ S and sulfur at high pressure, while H $_{3}$ S is stable at least up to 300 GPa. The other hydrogen-rich H $_{4}$ S, H $_{5}$ S, and H $_{6}$ S are unstable in the pressure range from 20 to 300 GPa.