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Density gradients for the exchange energy of electrons in two dimensions

Authors: S. Pittalis, E. Räsänen, J.G. Vilhena and M.A.L. Marques

Ref.: Phys. Rev. A 79, 012503 (2009)

Abstract: We present a generalized gradient approximation to the exchange energy to be used in density functional theory calculations of two-dimensional systems. This class of approximations has a long and successful history, but it has been not yet fully investigated for electrons in two dimensions. We follow the approach originally proposed by Becke for three-dimensional systems [Int. J. Quantum Chem. 23, 1915 (1983), J. Chem. Phys. 85, 7184 (1986)]. The resulting functional depends on two parameters that are adjusted to a test set of parabolically confined quantum dots. Our exchange functional is then tested on a variety of systems with promising results, reducing the error in the exchange energy by a factor of four with respect to the simple local density approximation.

DOI: 10.1103/PhysRevA.79.012503

URL: arxiv.org