Asphericity in the Fermi surface and Fermi energy of Li1−xBx (B = Na, K, Rb and Cs) substitutional alloys

A detailed investigation into asphericity in the Fermi surface (FS) and Fermi energy (FE) of Li1−xBx (B = Na, K, Rb and Cs) substitutional alloys are reported for the first time. The FE computed under pseudo-alloy-atom (PAA) model consideration is found higher than the FE computed under phase mixture (Mix) consideration. The non-linear relation for EF(x) = a0 + a1x + a2x2 is predicted for all the substantial binaries. The exchange and correlation effects are found to suppress the value of FE. The alloying behavior of Na, K, Rb and Cs with Li generates the asphericity in the FS like bcc metals. For Li1−xBx, the asphericity in the FS of the binary decreases with increase in x, except Li1−xCsx. In Li1−xCsx, the asphericity in the FS of the binary increases with increase in x. The Li1−xCsx solid solution shows maximum Fermi surface distortion (FSD) in comparison to Li1−xBx (B = Na, K and Rb) systems. Present study also concludes that the impact of local-field correction function on the asphericity in the FS is maximum at [1 0 0] point and minimum at [1 1 1] point. Among the high symmetry directions, the maximum asphericity in the FS is obtained at [1 1 0] point.