Godby, R.W., Gonze, X. and Ghosez, P. (1997) Density-functional theory of polar insulators. Physical Review Letters. pp. 294-297. ISSN 1079-7114Full text available as:
We examine the density-functional theory of macroscopic insulators, obtained in the large-cluster limit or under periodic boundary conditions. For polar crystals, we find that the two procedures are not equivalent. In a large-cluster case, the exact exchange-correlation potential acquires a homogeneous ``electric field'' which is absent from the usual local approximations, and the Kohn-Sham electronic system becomes metallic. With periodic boundary conditions, such a field is forbidden, and the polarization deduced from Kohn-Sham wavefunctions is incorrect even if the exact functional is used.
|Copyright, Publisher and Additional Information:||© 1997 American Physical Society. Published in Physical Review Letters and uploaded in accordance with the publisher's self archiving policy.|
|Institution:||The University of York|
|Academic Units:||The University of York > Physics (York)|
|Depositing User:||Physics Import|
|Date Deposited:||25 Sep 2008 12:49|
|Last Modified:||26 Mar 2015 07:37|