Full-potential nonorthogonal local-orbital minimum-basis band-structure scheme

We present a full-potential band-structure scheme based on the Linear combi nation of overlapping nonorthogonal orbitals. The crystal potential and den sity are represented as a lattice sum of local overlapping nonspherical con tributions. The decomposition of the exchange and correlation potential int o local parts is done using a technique of partitioning of unity resulting in local shape functions, which add exactly to unity in the whole crystal a nd which are very easily treated numerically. The method is all-electron, w hich means that core relaxation is properly taken into account. Nevertheles s, the eigenvalue problem is reduced to the dimension of a minimum valence orbital basis only. Calculations on sp and transition metals give results c omparable to other full-potential methods. The calculations on the diamond lattice demonstrate the applicability of our approach to open structures. T he consequent local description of all real-space functions allows the trea tment of substitutional disordered materials. [S0163-1829(99)09303-0].