FLAPW: applications and implementations

Abstract

Modern material design involves a close collaboration between experimental andcomputational materials scientists. To be useful, the theory must be able to accuratelypredict the stability and properties of new materials, describe the physics of theexperiments, and be applicable to new and complex structures—the all-electronfull-potential linearized augmented plane wave (FLAPW) is one such method that providesthe requisite level of numerical accuracy, albeit at the cost of complexity. Technical aspectsand modifications related to the choice of basis functions (energy parameters,core–valence orthogonality, extended local orbitals) that affect the applicabilityand accuracy of the method are described, as well as an approach for obtainingk-independent matrix elements. The inclusion of external electric fields is illustrated byresults for the induced densities at the surfaces of both magnetic and non-magnetic metals,and the relationship to image planes and to nonlinear effects such as second harmonicgeneration. The magnetic coupling of core hole excitations in Fe, the calculation of intrinsicdefect formation energies, the concentration-dependent chemical potentials, entropiccontributions, and the relative phase stability of Zr-rich Zr–Al alloys are also discussed.