arXiv subjects

W. -J. Zhu

Publications and source records attributed to W. -J. Zhu.

2 recordsLinked to original sources

arXiv2000

Effective potentials for 6-coordinated Boron: structural geometry approach

We have built a database of ab-initio total energies for elemental Boron in over 60 hypothetical crystal structures of varying coordination $Z$, such that every atom is equivalent. Fitting to each subset with a particular $Z$, we extract a classical effective potential, written as a sum over coordination shells and dominated by three-atom (bond angle dependent) terms. In the case Z=6 (lowest in energy and most relevant), the classical potential has a typical error of 0.1 eV/atom, and favours the ``inverted-umbrells'' environment seen in real Boron.

cond-mat.mtrl-sci↗

arXiv1998

Phonon-phason coupling in icosahedral quasicrystals

From relaxation simulations of decoration-based quasicrystal structure models using microscopically based interatomic pair potentials, we have calculated the (usually neglected) phonon-phason coupling constant. Its sign is opposite for the two alloys studied, i-AlMn and i-(Al,Cu)Li; a dimensionless measure of its magnitude relative to the phonon and phason elastic constants is of order 1/10, suggesting its effects are small but detectable. We also give a criterion for when phonon-phason effects are noticeable in diffuse tails of Bragg peaks.

cond-mat.mtrl-sci↗