Structure of solid-state systems from embedded-cluster calculations: A divide-and-conquer approach.

Abstract

The first-principles divide-and-conquer density-functional approach has been extended to solid-state systems. The method has the following features. (1) It divides a periodic solid-state system into equivalent primitive cells and further divides each cell into subsystems. The electron density of each subsystem is determined through the local representation of the one-electron Hamiltonian and used to form the total density per primitive cell. The method calculates the electronic structure of solids without involving the reciprocal space and its associated band structure. (2) It uses numerical atomic orbitals as basis functions with great variational flexibility. The Hamiltonian and other matrix elements are evaluated by numerical integration without any shape approximation to the effective one-electron potential. (3) This method, based on real space partition, can be applied to extended solid-state systems without translational symmetry, such as defects and surface chemisorption. As the first step, we have applied and tested the method to the electronic structure calculations of various crystalline solids: metallic lithium and copper, ionic sodium chloride, and covalent diamond and silicon. The self-consistently computed cohesive energies, structural properties, and density of states are in good agreement with those from the local-density approximation band-structure calculations and experimental results. \textcopyright{} 1996 The American Physical Society.