Abstract
The local-density approximation for the exchange-correlation potential understimates the fundamental band gaps of semiconductors and insulators by about 40%. It is argued here that underestimation of the gap width is also to be expected from the unknown exact potential of Kohn-Sham density-functional theory, because of derivative discontinuities of the exchange-correlation energy. The need for an energy-dependent potential in band theory is emphasized. The center of the gap, however, is predicted exactly by the Kohn-Sham band structure.
Keywords
Kohn–Sham equationsClassification of discontinuitiesBand gapDensity functional theoryPhysicsLocal-density approximationDerivative (finance)Condensed matter physicsQuantum mechanicsElectronic band structureOrbital-free density functional theorySemiconductorMathematical analysisMathematics
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Publication Info
- Year
- 1983
- Type
- article
- Volume
- 51
- Issue
- 20
- Pages
- 1884-1887
- Citations
- 2445
- Access
- Closed
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Cite This
John P. Perdew,
Mel Levy
(1983).
Physical Content of the Exact Kohn-Sham Orbital Energies: Band Gaps and Derivative Discontinuities.
Physical Review Letters
, 51
(20)
, 1884-1887.
https://doi.org/10.1103/physrevlett.51.1884
Identifiers
- DOI
- 10.1103/physrevlett.51.1884