M. J. Cawkwell D. Nguyen-Manh D. G. Pettifor V. Vitek
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…
PublishedD. A. Murdick X. W. Zhou H. N. G. Wadley D. Nguyen-Manh R. Drautz D. G. Pettifor
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 …
PublishedRalf Drautz Dewey A. Murdick Duc Nguyen-Manh Xiaowang Zhou Haydn N. G. Wadley David G. Pettifor
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…
PublishedK. Kohary V. M. Burlakov D. G. Pettifor
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…
PublishedGuoqiang Liu D. Nguyen-Manh Bang-Gui Liu D. G. Pettifor
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…
PublishedD. A. Pankhurst Z. Yuan D. Nguyen-Manh M.-L. Abel G. Shao J. F. Watts D. G. Pettifor P. Tsakiropoulos
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