Structural and Superconducting Parameters of Highly Compressed H3S

The discovery of superconductivity in pressurized H3S 1 initiated a wide range of experimental and theoretical studies of compressed hydrides in which room-temperature superconductivity is in demand. Recently, a new milestone progress has been reported in the field, namely, direct measurements of the superconducting gap amplitude (T) in highly compressed sulfur 46, H3S and D3S 47. This study examines recent experimental XRD data reported on H3S 47 and found that H3S (at pressure 151\; < P < 158~\, GPa) exhibits nanosized grains with average size D = 24 ± 2 nm and remarkably low microstrain ε = 0. 07 ± 0. 04%. Further analysis of reported experimental data shows that the H3S has the Debye temperature {{{ }}₃} = 1294 24\, ~K, the electron–phonon coupling constant { {₄ - {ph}}} = 2. 30, specific heat jump at the superconducting transition temperature {{C{{₄₋}}}}{ {{T₂}}} = 1. 5 0. 6, and gap-to-transition temperature ratio 2 (0) {{{k₁}{T₂}}} = 3. 7 0. 3. The derived values are in a good agreement with the values calculated by first-principles calculations.