An Investigation of Superconducting Properties of Some Alkali Doped (A=Li, Na, K, Rb, Cs) Fe Based Superconductors – A First Principles Study

Abstract

The superconducting properties of alkaline doped Iron based superconductors (L=Li, Na, K, Rb, Cs) compounds were investigated using the ab-initio method. The studies were concentrated on investigatingthe electronic band structure, Fermi surface and superconducting properties of these materials. These compounds are having tetragonal structure (space group=129) with the P4/nmm. Plane wave calculations were performed by Wien2K code using the self-consistent method. To study the electronic structure and magnetic ordering, the Brich-Murnaghan equation was used. The estimated lattice parameters are comparable with the available experimental data. Density of states values at the Fermi level are found to increase continuously with increasing ionic radius of the dopent ion. The low value of electron phonon coupling constant may be attributedto increase in bond angle of A-Fe-A, Fe-A distances and degraded Fermi surface nesting. The absolute Fe magnetization of LiFeAs and NaFeAs are larger than other Alkali (A= K, Rb, Cs) compounds. Finally, the electron-phonon coupling constant (λ) values are found to decrease continuously