Hole-doped room-temperature superconductivity in H₃S_1-xZ_x (Z=C, Si)

We examine the effects of the low-level substitution of S atoms by C and Si atoms on the superconductivity of H₃S with the Im3¯m structure at megabar pressures. The hole doping can fine-tune the Fermi energy to reach the electronic density-of-states peak maximizing the electron-phonon coupling. This can boost the critical temperature from the original 203 K to 289 K and 283 K, respectively, for H₃S_0.962C_0.038 at 260 GPa and H₃S_0.960Si_0.040 at 230 GPa. The former may provide an explanation for the recent experimental observation of room-temperature superconductivity in a highly compressed C–S–H system [Nature 586, 373–377 (2020)]. Our work opens a new avenue for substantially raising the critical temperatures of hydrogen-rich materials.