The atomic structure of icosahedral B4C boron carbide is determined by comparing existing infra-red absorption and Raman diffusion measurements with the predictions of accurate {\it ab initio} lattice-dynamical calculations performed for different structural models. This allows us to unambiguously determine the location of the carbon atom within the boron icosahedron, a task presently beyond X-ray and neutron diffraction ability. By examining the inter- and intra-icosahedral contributions to the stiffness we show that, contrary to recent conjectures, intra-icosahedral bonds are harder.
@article{arxiv.cond-mat/9909182,
title = {Atomic structure and vibrational properties of icosahedral B$_4$C boron carbide},
author = {R. Lazzari and N. Vast and J. M. Besson and S. Baroni and A. Dal Corso},
journal= {arXiv preprint arXiv:cond-mat/9909182},
year = {2009}
}
Comments
9 pages including 3 figures, accepted in Physical Review Letters