All-electron spin-polarized relativistic linearized APW method: Electronic and magnetic properties of BCC Fe, HCP Gd and uranium monochalcogenides

The linearized-augmented-plane-wave (LAPW) method is generalized to case of an all-electron fully-relativistic spin-polarized self-consistent hand calculation based on the relativistic spin-density functional theory. Inside spheres around nuclei: the Bloch function is expanded by spherical-symmetry bases and their energy-derivatives, each of which is solved by the corresponding spin-polarized coupled Dirac equation (SPCDE) including a coupling of j = l - 1/2 with j = l+1/2 partial state through the magnetic field. In the interstitial region, the relativistic plane wave is used as a conventional basis function. The core states inside the spheres are treated on the same footing of the SPCDE in all iterative processes. This band theory is applied to BCC Fe, HCP Gd and uranium monochalcogenides US, USe and UTe as an interesting example of the ferromagnetic 3d, 4f and 5f systems, respectively. The electronic hand structures are shown together with the spin and orbital moments.