Parametrisation of the LCAO Bandstructure of BCC Transition Metals

Abstract

In this paper we present a direct parameter fitting scheme appropriate to a linear combination of atomic orbitals (LCAO) model· Hamiltonian representation of the BCC transition metals incorporating first and second neighbour interactions. Explicit expressions are given for the one-electron eigenvalues at all of the important symmetry points of the BCC Brillouin zone. This direct parameter fitting scheme is shown to produce an excellent representation of the bandstructure of paramagnetic iron, and yields parameter values little different from those obtained from a full least-squares optimisation of the LCAO model Hamiltonian bandstructure. The extension of this scheme to include more distant interactions, and relativistic and spin-orbit effects, is also discussed.