Full-potential linear muffin-tin-orbital method
Abstract
A new band-structure method which allows the self-consistent solution of the Schr\"odinger equation with a full (all-electron, non-muffin-tin) crystal potential has been developed. A basis set consisting of the 9 (16) s, p, and d (f) linear-muffin-tin orbitals per site is used. The wave functions as well as the electron density and the potential are split into a smooth ``pseudo'' part, which is expanded in plane waves, and local parts, which are expressed as spherical-harmonics one-center expansions. The total-energy functional of density-functional theory is evaluated without any shape approximation. The usefulness and accuracy of the method is demonstrated by applying it to a ``frozen phonon'' in silicon and comparing the results with experiment. The calculated phonon frequency and anharmonic term are in excellent agreement with the experimental data. The method is generally applicable to systems with delocalized as well as localized orbitals.