Modulating superconductivity in elementary materials by doping

Influenced by the discovery of high-temperature superconductivity in compressed hydrides, the search for superconductors with high transition temperatures has received growing attention. Here, based on first-principles calculations, the influence of doping on superconducting properties of five elementary materials (i.e., Mo, Nb, Pb, Al, Zr) is studied. The electron-phonon coupling strength and transition temperature can always be effectively increased due to both phonon softening and increased contribution of some specific phonons either by electron doping or hole doping. For each material, there is an optimum doping level with highest transition temperature. Our work highlights the crucial role of doping in raising the transition temperature of traditional Bardeen-Cooper-Schrieffer superconductors.