Dynamical-charge neutrality at a crystal surface
Materials Science
2009-10-30 v1
Abstract
For both molecules and periodic solids, the ionic dynamical charge tensors which govern the infrared activity are known to obey a dynamical neutrality condition. This condition enforces their sum to vanish (over the whole finite system, or over the crystal cell, respectively). We extend this sum rule to the non trivial case of the surface of a semiinfinite solid and show that, in the case of a polar surface of an insulator, the surface ions cannot have the same dynamical charges as in the bulk. The sum rule is demonstrated through calculations for the Si-terminated SiC(001) surface.
Cite
@article{arxiv.cond-mat/9701194,
title = {Dynamical-charge neutrality at a crystal surface},
author = {Alice Ruini and Raffaele Resta and Stefano Baroni},
journal= {arXiv preprint arXiv:cond-mat/9701194},
year = {2009}
}
Comments
4 pages, latex file, 1 postscript figure automatically included