First-principles study of superconducting hydrogen sulfide at pressure up to 500 GPa

We investigate the possibility of achieving the room-temperature superconductivity in hydrogen sulfide (H₃S) through increasing external pressure, a path previously widely used to reach metallization and superconducting state in novel hydrogen-rich materials. The electronic properties and superconductivity of H₃S in the pressure range of 250-500 GPa are determined by the first-principles calculations. The metallic character of a body-centered cubic Im3 ¯ m structure is found over the whole studied pressure. Moreover, the absence of imaginary frequency in phonon spectrum implies that this structure is dynamically stable. Furthermore, our calculations conducted within the framework of the Eliashberg formalism indicate that H₃S in the range of the extremely high pressures is a conventional strong-coupling superconductor with a high superconducting critical temperature, however, the maximum critical temperature does not exceed the value of 203 K.