Superconductivity in hydrogen sulfide in the presence of carbon*

 

We examine the role of carbon in superconducting hydrogen sulfide. We obtained a number of unique structures from a simulation cell containing carbon, hydrogen. and sulfur atoms with randomized atomic coordinates. We also reproduced some structures reported in the literature. In general, the presence of carbon atoms does not raise the superconducting transition temperature of hydrogen sulfide compounds. We discuss the origin of this trend by a detailed examination of structural and electronic properties in these systems.