Metallization and superconductivity in methane doped by beryllium at low pressure.

As one of the simplest hydrocarbons, methane (CH) has great potential in the research of superconductors. However, the metallization of CH has been an issue for a long time. Here, we report the structure, metallization, and superconductivity of CH doped by Be at low pressures, based on first-principles calculations. The result shows that the thermodynamically stable BeCH with P1[combining macron] space-group can transform into a metal at ambient pressure. This ternary hydride BeCH exhibits a superconductivity of ∼6 K below 25.6 GPa. Interestingly, the superconducting critical temperature of BeCH can reach ∼30 K at 80 GPa in the form of an a-P1 space-group phase. The charge transfer from Be to CH molecules plays an important role in the superconductivity. Our results present a novel way to realize the metallization of methane at relative pressures and indicate that the doped methane is a potential candidate for seeking high temperature and low pressure superconductivity.