First-Principles Study on Superconductivity of P- and Cl-Doped H3S

Recent reports on 203 K superconductivity in compressed sulfur hydride (H₃S) have attracted considerable interest in sulfur-hydrogen systems under high pressure. Here, we investigated the superconductivity of P- and Cl-doped H₃S using first-principles calculations based on the supercell method, which gives more reliable results on the superconductivity in doped systems than the calculations based on the virtual crystal approximation reported earlier. The superconducting critical temperature is increased from 189 to 212 K at 200 GPa in the cubic Im\bar{3}m phase by 6.25% P doping, whereas it is decreased to 161 K by 6.25% Cl doping. Although the Cl doping weakens the superconductivity, it causes the Im\bar{3}m phase to be stabilized in a pressure region lower than that in the nondoped H₃S.