Electronic structure and superconducting properties of lanthanum

The total energy and electronic structure of lanthanum have been calculated in the bcc, fcc, hcp, and double hcp structures for pressures up to 35 GPa. The full-potential linearized-augmented-plane-wave method was used with both the local-density approximation (LDA) and generalized-gradient approximation (GGA). The correct phase ordering has been found by the GGA results, with lattice parameters and bulk moduli in good agreement with experimental data. The GGA method shows excellent agreement with experiment while the LDA results show some discrepancies. The calculated strain energies for the fcc and bcc structures demonstrate the respective stable and unstable configurations at ambient conditions. The calculated superconductivity properties under pressure for the fcc structure are also found to agree well with measurements. Both LDA and GGA, with minor differences, reproduce well the experimental results for the superconducting critical temperature ${T}_{c}$.