Method for calculating electronic structures near surfaces of semi-infinite crystals

We present a stable scheme to calculate continum and bound electronic states in the vicinity of a surface of a semi-infinite crystal within the framework of density functional theory. The method is designed for solution of the Kohn-Sham equations in a pseudpotential formulation, including both local and separable nonlocal contributions. The method is based on the Numerov integration algorithm and uses singular value decomposition to control the exponentially growing contributions. The method has been successfully tested on the Li 110 surface with and without adsorbed H. For this model system, we are able to locate the energies of H-induced surface states relative to the corresponding energies of bulk continum states. Results encourage further development.