Onedimensional oxygen ordering in YBa_{2}Cu_{3}O_{7δ}
Abstract
A model consisting of oxygenoccupied and vacant chains is considered, with repulsive first and secondnearestneighbor interactions V_{1} and V_{2}, respectively. The statistical mechanics and the diffraction spectrum of the model are solved exactly and analytically with the only assumption V_{1}>>V_{2}. At temperatures T~V_{1} only a broad maximum at (1/2,0,0) is present, while for δ1/2>1/14 at low enough T, the peak splits into two. The simple expression for the diffraction intensity obtained for T<<V_{1} represents in a more compact form previous results of Khachaturyan and Morris, extends them to all δ and T/V_{2}, and leads to a good agreement with experiment.
 Publication:

Physical Review B
 Pub Date:
 June 1993
 DOI:
 10.1103/PhysRevB.47.15308
 arXiv:
 arXiv:condmat/9305002
 Bibcode:
 1993PhRvB..4715308A
 Keywords:

 74.72.Bk;
 61.14.Hg;
 64.60.Cn;
 Ybased cuprates;
 Lowenergy electron diffraction and reflection highenergy electron diffraction;
 Orderdisorder transformations;
 statistical mechanics of model systems;
 Condensed Matter
 EPrint:
 13 pages,Revtex,3 figures available upon request but can be plotted using simple analytical functions,CNEACAB 92/042