Full Potential, Total Energy Lmto Calculation of Interface Structure in Ti-C and W-C Superlattices

We discuss calculations of the electronic and crystallographic structure at the interfaces of titanium-carbon and tungsten-carbon superlattices. Specifically, we present total energy calculations for an arrangement of atoms designed to allow direct investigation of the competition between the formation of M-C bonds and C-C bonds. We conclude that the equilibrium structure is dominated by C-C bonding and so find that the interface has a graphite-like atomic arrangement rather than a carbide-like arrangement. These total energy calculations have been performed using a recently developed self-consistent linear combination of muffin-tin orbitals electronic structure method. This is a full-potential, all-electron, variation on standard LMTO electronic structure methods and, along with careful self-consistent determination of the parameters involved, allows accurate total energy calculations of the type of low symmetry systems involved in this study.