Linear-scaling total-energy calculations with the tight-binding Korringa-Kohn-Rostoker Green function method

A complex-energy broadening scheme with quartic dependence on the broadening parameter is presented for Green function density-functional electronic-structure calculations. The scheme is applied in a recently developed linear-scaling algorithm based on the tight-binding Korringa-Kohn-Rostoker Green function method where it leads to considerable computational saving compared to the standard Fermi-Dirac broadening with quadratic dependence. The linear-scaling algorithm is applied for total-energy and spin-moment calculations for large supercells and the advantages of the quartic broadening scheme are discussed.