The Superconducting Properties of Elemental Pb Under Pressure

Based on first-principles calculations, we systematically investigate the crystal structure, electronic structure, and superconductivity of metallic lead under pressure. The results show that with the increase of pressure, the crystal structure of lead evolves from face-centered cubic (fcc) to hexagonal close-packed (hcp) and then to body-centered cubic (bcc). In different crystal structure phases, the variation laws of electronic structure and superconducting properties with pressure are studied. It is found that the superconducting transition temperature decreases with the increase of pressure in fcc, hcp, and bcc phases. The physical mechanism for this change is explained. The calculation results indicate that elemental metallic lead remains metallic with the increase of pressure, but the electron density of states at the Fermi level decreases, leading to the decrease of the electron-phonon coupling constant (λ) and superconducting transition temperature (Tc) from 7.1 K to 0.04 K. In addition, with the increase of pressure, there is no phenomenon of s electrons transforming into d electrons, which is different from the superconducting behavior of zirconium metal under pressure. These studies explain the superconductivity of elemental metallic lead under high pressure and provide theoretical support for the experiments and applications of lead-based superconductors.