Ab Initio Investigation on the Doped H3S by V, VI, and VII Group Elements Under High Pressure

The influence of doping on the high-T-c superconductor Im-3 m-H3S has attracted great attention since the addition of the external elements is expected to further increase the T-c value or lower the stable pressure of H3S. Here, we systematically investigated the electronic structures and superconductive properties of H6SX (X = N, P, As, O, Se, F, Cl, and Br) through first-principle calculations at 200 GPa. Only H6SP, H6SSe, and H6SBr are dynamically stable and the T-c of H6SSe can reach 182 K. The bonding analysis shows that stronger covalent interactions are beneficial for higher T-c values for these ternary metallic covalent superconductors. The improvement of T-c in doped H3S systems could be obtained through introducing stronger covalent interactions and light atomic massive. In addition, we found that the replacement of Br atoms can reduce the stable pressure of H3S to 150 GPa with T-c about 159-174 K.