MOLECULAR-DYNAMICS-SIMULATION STUDY OF THE 2-DIMENSIONAL LATTICE STRUCTURE OF THE CU-1 PLANE IN YBA2CU3O6+X

A molecular-dynamics (MD) simulation was used to study tile two-dimens ional (2D) structure of a YBa2Cu3O6+x cuprate plane, which forms a squ are lattice in the insulating state. The simulation was performed on a n arbitrary Cu-1 plane in a cell, taking into account interactions wit h atoms located on nearest-neighbor planes. A layered 2D screened-Coul omb potential developed by Fan and Malozovsky [Phys. Rev. B 49, 4334 ( 1994) and J. Phys. Chem. Solids 11, 1677 (1996)] is found to be suffic ient to produce the square lattice structure. This pair potential is d erived microscopically, accounting for the exchange correlation effect s in a layered lattice with an isotropic 2D electron spectrum; the MD results support the validity of the potential. [S0163-1829(97)05341-1] .