Abstract for the talk at 21.05.2007 (12:00 h)Oberseminar MATERIALS
Ralf Drautz (University of Oxford)
Valence-dependent analytic bond-order potential for transition metals
The derivation of robust interatomic potentials is a key step for bridging from the electronic to the atomistic modelling hierarchies in materials science. We present an analytic interatomic bond-order potential (BOP) that depends explicitly on the valence of the transition metal element . This analytic potential predicts the structural trend from hcp to bcc to hcp to fcc that is observed across the non-magnetic 4d and 5d transition metal series. The potential also describes the different ferromagnetic moments of the alpha (bcc), gamma (fcc) and epsilon (hcp) phase of the 3d transition metal iron, the difference between the ferromagnetic and anti-ferromagnetic states as well as non-collinear spin-configurations. In addition, this new potential includes a correct description of alloy bonding within its remit. In this talk we will show how the potential is derived from the tight-binding electronic structure and demonstrate that it may be regarded as a systematic extension of the second-moment Finnis-Sinclair potential to include higher moments.  R. Drautz and D.G. Pettifor, Phys. Rev. B 74, 174117 (2006).