UKAEA Journals

Showing 1 - 6 of 6 Journals Results
2007

A tight-binding based bond-order potential BOP has been constructed for the fcc transition metal iridium that includes explicitly only d orbitals in the evaluation of the total energy.We show that hybridization between the nearly free electron sp band and the unsaturated covalently bonded d orbitals is important in determining the relative stabilit…

Published
2006

An analytic, bond-order potential BOP is proposed and parametrized for the gallium arsenide system. The potential addresses primary and secondary bonding and the valence-dependent character of heteroatomic bonding, and it can be combined with an electron counting potential to address the distribution of electrons on the GaAs surface. The potential …

Published
2005

An analytic interatomic bond-order potential BOP is derived that depends explicitly on the group number of the sp -valent element. This is achieved by generalizing the previously published BOP for group-IV elements by extrapolating from half-full occupancy using a simple envelope function for the upper bound of the bond order. This interatomic pote…

Published
2005

The structure of amorphous In x Se y alloys has been studied by a first principles tight-binding molecular dynamics technique. The three-dimensional amorphous structures with different densities at different compositions were prepared by quick quenching from the liquid phase. The characteristics of short-range order, namely radial distribution func…

Published
2005

The tight-binding Stoner model of band magnetism is generalized to account for local charge neutrality by working within the tight-binding-bond s TBB d representation of the binding energy. We show that the analytic forces within this TBB Stoner model take a very simple form because neither the renormalization in the on-site energies due to local c…

Published
2005

We have investigated the electronic structure of MoSi2, Mo5Si3, Mo3Si, and Mo(Si1−xAlx)2 alloys at a range of x values using a combination of valence-band x-ray photoelectron spectroscopy sVBXPSd and densityfunctional theory. We find good agreement between the experimental spectra and the calculated total densities of states. The observed differe…

Published