1999/09/30 by Nicholas J. Ramer, Andrew M. Rappe · 5 citations
Materials Science · Physics and Astronomy · #Ferroelectric and Piezoelectric Materials #Phase-change materials and chalcogenides #Solid-state spectroscopy and crystallography #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.62.r743
5 pages, no figures
arxiv created 2000/04/25 · openalex publication_date 2000/07/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We present a method for modeling disordered solid solutions, based on the virtual crystal approximation (VCA). The VCA is a tractable way of studying configurationally disordered systems; traditionally, the potentials which represent atoms of two or more elements are averaged into a composite atomic potential. We have overcome significant shortcomings of the standard VCA by developing a potential which yields averaged atomic properties. We perform the VCA on a ferroelectric oxide, determining the energy differences between the high-temperature rhombohedral, low-temperature rhombohedral, and tetragonal phases of Pb(Zr_1\ensuremath-xTix)O3 at x=0.5 and comparing these results to superlattice calculations and experiment. We then use our method to determine the preferred structural phase at x=0.4. We find that the low-temperature rhombohedral phase becomes the ground state at x=0.4, in agreement with experimental findings.