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Electronic structures are fully determined by the exchange-correlation (XC) potential. In this work, we develop a new method to construct reliable XC potentials by properly mixing the exact exchange and the local density approximation…

Chemical Physics · Physics 2024-08-06 Chen Huang

A simple exact-exchange density-functional method for a quasi-two-dimensional electron gas with variable density is presented. An analytical expression for the exact-exchange potential with only one occupied subband is provided, without…

Condensed Matter · Physics 2009-11-07 F. A. Reboredo , C. R. Proetto

Bounds on the exchange-correlation energy of many-electron systems are derived and tested. By using universal scaling properties of the electron-electron interaction, we obtain the exponent of the bounds in three, two, one, and quasi-one…

Strongly Correlated Electrons · Physics 2009-05-21 E. Rasanen , S. Pittalis , K. Capelle , C. R. Proetto

Most density functionals have been developed by imposing the known exact constraints on the exchange-correlation energy, or by a fit to a set of properties of selected systems, or by both. However, accurate modeling of the conventional…

Materials Science · Physics 2016-08-24 Jianmin Tao , Yuxiang Mo

The flexibility of common generalized gradient approximation for the exchange-correlation energy is investigated by monitoring the equilibrium volume of transition metals. It is shown that no universal gradient-level approximation yielding…

Materials Science · Physics 2015-06-05 H. Levämäki , L. Vitos , M. P. J. Punkkinen , K. Kokko

We train a neural network as the universal exchange-correlation functional of density-functional theory that simultaneously reproduces both the exact exchange-correlation energy and potential. This functional is extremely non-local, but…

Computational Physics · Physics 2019-10-10 Jonathan Schmidt , Carlos L. Benavides-Riveros , Miguel A. L. Marques

We show that the exact exchange-correlation potential of time-dependent density-functional theory displays dynamical step structures that have a spatially non-local and time non-local dependence on the density. Using one-dimensional…

Chemical Physics · Physics 2015-06-12 Peter Elliott , Johanna I. Fuks , Angel Rubio , Neepa T. Maitra

Implicit and explicit density functionals for the exchange energy in finite two-dimensional systems are developed following the approach of Becke and Roussel [Phys. Rev. A 39, 3761 (1989)]. Excellent agreement for the exchange-hole…

Strongly Correlated Electrons · Physics 2008-05-08 S. Pittalis , E. Rasanen , N. Helbig , E. K. U. Gross

In this paper we present a new approach how to extract polarization-dependent exchange-correlation energy densities for two-dimensional systems from reference densities and energies of quantum dots provided by exact diagonalization.…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Andreas Wensauer , Ulrich Rössler

In modeling low-dimensional electronic nanostructures, the evaluation of the electron-electron interaction is a challenging task. Here we present an accurate and practical density-functional approach to the two-dimensional many-electron…

Strongly Correlated Electrons · Physics 2010-10-29 S. Pittalis , E. Rasanen

A long-standing puzzle in density-functional theory is the issue of the long-range behavior of the Kohn-Sham exchange-correlation potential at metal surfaces. As an important step towards its solution, it is proved here, through a rigurouos…

Materials Science · Physics 2015-05-18 C. M. Horowitz , C. R. Proetto , J. M. Pitarke

We investigate fundamental properties of meta-generalized-gradient approximations (meta-GGAs) to the exchange-correlation energy functional, which have an implicit density dependence via the Kohn-Sham kinetic-energy density. To this…

Chemical Physics · Physics 2014-12-10 F. G. Eich , Maria Hellgren

We test local and semi-local density functionals for the electronic exchange for a variety of systems including atoms, molecules, and atomic chains. In particular, we focus on a recent universal extension of the Becke-Johnson exchange…

Materials Science · Physics 2010-11-01 Micael J. T. Oliveira , Esa Räsänen , Stefano Pittalis , Miguel A. L. Marques

Density function theory is the workhorse of modern electronic structure theory. However, its accuracy in practical calculations is limited by the choice of the exchange-correlation potential. In this respect, two-dimensional materials pose…

Materials Science · Physics 2026-04-29 Michael Lorke

We derive an exact representation of the exchange-correlation energy within density functional theory (DFT) which spawns a class of approximations leading to correct long-range asymptotic behavior. In what amounts to be the simplest…

Materials Science · Physics 2009-11-10 Roi Baer , Daniel Neuhauser

We report simple expressions for the exchange coupling in double quantum dots calculated within the Heitler-London and the Hund-Mulliken approximations using four different confining potentials. At large interdot distances and at large…

Mesoscale and Nanoscale Physics · Physics 2010-05-18 Jesper G. Pedersen , Christian Flindt , Antti-Pekka Jauho , Niels Asger Mortensen

We construct a meta-generalized-gradient approximation which properly balances the nonlocality contributions to the exchange and correlation at the semilocal level. This non-empirical functional shows good accuracy for a broad palette of…

Chemical Physics · Physics 2013-05-17 L. A. Constantin , E. Fabiano , F. Della Sala

We identify peak and valley structures in the exact exchange-correlation potential of time-dependent density functional theory that are crucial for time-resolved electron scattering in a model one-dimensional system. These structures are…

Chemical Physics · Physics 2018-01-03 Yasumitsu Suzuki , Lionel Lacombe , Kazuyuki Watanabe , Neepa T. Maitra

When using the boundary integral equation method to solve a boundary value problem, the evaluation of the solution near the boundary is challenging to compute because the layer potentials that represent the solution are nearly-singular…

Numerical Analysis · Mathematics 2018-10-08 Camille Carvalho , Shilpa Khatri , Arnold D. Kim

Density functional theory is the workhorse of modern electronic structure calculations, with wide-ranging applications in chemistry, physics, materials science, and machine learning. At its heart lies the exchange-correlation functional, a…

Chemical Physics · Physics 2026-02-20 Fabien Tran , Susi Lehtola , Stefano Pittalis , Miguel A. L. Marques