Koopmans' condition for density-functional theory
- CERMICS, Projet Micmac ENPC-INRIA, Universite Paris-Est, 6-8 avenue Blaise Pascal, 77455 Marne-la-Vallee Cedex 2 (France)
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
- Department of Physics, Institute of Theoretical Physics and Astrophysics, and Fujian Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005 (China)
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
In approximate Kohn-Sham density-functional theory, self-interaction manifests itself as the dependence of the energy of an orbital on its fractional occupation. This unphysical behavior translates into qualitative and quantitative errors that pervade many fundamental aspects of density-functional predictions. Here, we first examine self-interaction in terms of the discrepancy between total and partial electron removal energies, and then highlight the importance of imposing the generalized Koopmans' condition - that identifies orbital energies as opposite total electron removal energies - to resolve this discrepancy. In the process, we derive a correction to approximate functionals that, in the frozen-orbital approximation, eliminates the unphysical occupation dependence of orbital energies up to the third order in the single-particle densities. This non-Koopmans correction brings physical meaning to single-particle energies; when applied to common local or semilocal density functionals it provides results that are in excellent agreement with experimental data - with an accuracy comparable to that of GW many-body perturbation theory - while providing an explicit total energy functional that preserves or improves on the description of established structural properties.
- OSTI ID:
- 21421419
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 11; Other Information: DOI: 10.1103/PhysRevB.82.115121; (c) 2010 The American Physical Society; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCURACY
APPROXIMATIONS
CORRECTIONS
DENSITY
DENSITY FUNCTIONAL METHOD
ELECTRONS
FORECASTING
INTERACTIONS
MANY-BODY PROBLEM
PERTURBATION THEORY
CALCULATION METHODS
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
PHYSICAL PROPERTIES
VARIATIONAL METHODS