From: David Vanderbilt <dhv@physics.rutgers.edu> Date: Sun, 25 May 1997 11:37:52 -0400 (14kb)
Authors:
David Vanderbilt (Department of Physics and Astronomy, Rutgers University)
Comments: 4 pages, two-column style with 2 postscript figures embedded. Uses
REVTEX and epsf macros. Also available at
this http URL
Subj-class: Materials Science
The theory of the macroscopic field appearing in the Kohn-Sham exchange-correlation potential for dielectric materials, as introduced by Gonze, Ghosez and Godby, is reexamined. It is shown that this Kohn-Sham field cannot be determined from a knowledge of the local state of the material (local crystal potential, electric field, and polarization) alone. Instead, it has an intrinsically nonlocal dependence on the global electrostatic configuration. For example, it vanishes in simple transverse configurations of a polarized dielectric, but not in longitudinal ones.