High-pressure band structure and superconductivity of bcc and fcc lithium

Abstract

The electronic band structure, density of states, Fermi surface cross sections and superconductivity of bcc and fcc lithium (Li) as a function of pressure are investigated. The high-pressure band structure exhibits significant deviations from the normal-pressure band structure due to s→p transition. At normal pressure, the superconducting transition of bcc-Li occurs at 0.12mK. On further increase of pressure, Tc increases considerably and its maximum value may exceed 40K (at 1.65Mbar) both in bcc and fcc lithium. At 0.48Mbar pressure, the calculated value of Tc is very close to the experimental value of 20K. The high-pressure bcc and fcc lithium Fermi surfaces are distorted spheres with necks along the ΓN and ΓL directions, respectively. The nonlinear increase of Tc(P) is connected with the non-linear variation of the radius [kF(P)] of the Fermi surface neck at high pressure. Our results indicate that, Li is a one-band rather than a one-electron metal. The electron-phonon interaction parameter (λ) and its variation under pressure are structure independent in lithium, and Li is an electron-phonon mediated superconductor.

Source-reported materials — not catalogue approval

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