Novel properties of the Kohn-Sham exchange potential for open systems: application to the two-dimensional electron gas

Abstract

The properties of the Kohn-Sham (KS) exchange potential for open systems in thermodynamical equilibrium, where the number of particles is non-conserved, are analyzed with the Optimized Effective Potential (OEP) method of Density Functional Theory (DFT) at zero temperature. The quasi two-dimensional electron gas (2DEG) is used as an illustrative example. The main findings are that the KS exchange potential builds a significant barrier-like structure under slight population of the second subband, and that both the asymptotic value of the KS exchange potential and the inter-subband energy jump discontinuously at the one-subband (1S) -> two-subband (2S) transition. The results obtained in this system offer new insights on open problems of semiconductors, such as the band-gap underestimation and the band-gap renormalization by photo-excited carriers.

7 pages, 3 figures, uses epl.cls(included), accepted for publication in Europhysics Letters

References in corpus (5)

• Simple iterative construction of the optimized effective potential for orbital functionals, including exact exchange
• Optimized Effective Potential made simple: Orbital functionals, orbital shifts, and the exact Kohn-Sham exchange potential
• Excitonic optical spectrum of semiconductors obtained by time-dependent density-functional theory with the exact-exchange kernel
• Exact-exchange density-functional theory for quasi-two-dimensional electron gases
• Exact-Exchange Density Functional Theory applied to a strongly inhomogeneous electron gas

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