Theoretical Study of Lattice Instabilities in YBa₂Cu₃O₇

Authors

D. P. Billesbach, University of Nebraska-LincolnFollow
John R. Hardy, University of Nebraska-LincolnFollow
P. J. Edwardson, L! S. Naval Research Laboratory, Washington, D. C.

Date of this Version

1-1-1989

Comments

Published in Physical Review B Volume 39, Number 1, 1 January 1989. Copyright © 1989 The American Physical Society. Used by permission.

Abstract

We have performed a molecular dynamics simulation of the YBa₂Cu₃O₇ structure under the constraints of the rigid-ion model. These simulations used a variety of charge states for the Cu ions and the O ions, and except for one case, the interionic potentials were obtained in an ab initio fashion. The results of these simulations showed that a lattice instability involving the Cu-O chains existed. This instability was further investigated and it was shown that simple electronic screening is probably insufficient to stabilize the lattice. An instability of this nature provides a simple explanation of some experimentally observed phenomena.