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Density functional calculations for the electronic conductance of single molecules are now common. We examine the methodology from a rigorous point of view, discussing where it can be expected to work, and where it should fail. When…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Max Koentopp , Connie Chang , Kieron Burke , Roberto Car

A spin angular gradient approximation for the exchange correlation magnetic field in the density functional formalism is proposed. The usage of such corrections leads to a consistent spin dynamical approach beyond the local approximation.…

Strongly Correlated Electrons · Physics 2009-11-07 M. I. Katsnelson , V. P. Antropov

We derive a time-dependent density functional theory appropriate for calculating the near-edge X-ray absorption spectrum in molecules and condensed matter. The basic assumption is to increase the space of many-body wave functions from one…

Strongly Correlated Electrons · Physics 2015-06-16 G. F. Bertsch , A. Lee

Since Spin Density Functional Theory was first proposed, but also recently, examples were constructed to show that a spin-potential may share its ground state with other spin-potentials. In fact, for collinear magnetic fields and systems…

Other Condensed Matter · Physics 2013-05-29 Nikitas I. Gidopoulos

The problem of capturing physical spin torques in non-collinear magnetic systems has dominated the scene of spin-density functional theory (SDFT) in the last two decades. Progress has been hindered by the fact that the spin torque is…

Materials Science · Physics 2026-01-08 Jacques K. Desmarais , Kamel Bencheikh , Giovanni Vignale , Stefano Pittalis

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 study a model quantum dot system in an external magnetic field by using both the spin-density-functional theory and the current-spin-density-functional theory. The theories are used with local approximations for the spin-density and the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 H. Saarikoski , E. Räsänen , S. Siljamäki , A. Harju , M. J. Puska , R. M. Nieminen

The description of interacting many-electron systems in external magnetic fields is considered in the framework of the optimized effective potential method extended to current-spin-density functional theory. As a case study, a…

Materials Science · Physics 2011-01-14 N. Helbig , S. Kurth , S. Pittalis , E. Räsänen , E. K. U. Gross

We propose a systematic and constructive way to determine the exchange-correlation potentials of density-functional theories including vector potentials. The approach does not rely on energy or action functionals. Instead it is based on…

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

Density Functional Theory has long struggled to obtain the exact exchange-correlational (XC) functional. Numerous approximations have been designed with the hope of achieving chemical accuracy. However, designing a functional involves…

Chemical Physics · Physics 2025-03-10 Aditi Singh , Eduardo Fabiano , Szymon Śmiga

A description of non-collinear magnetism in the framework of spin-density functional theory is presented for the exact exchange energy functional which depends explicitly on two-component spinor orbitals. The equations for the effective…

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 fundamental gap of an interacting many-electron system is given by the sum of the single-particle Kohn-Sham gap and the derivative discontinuity. The latter can be generated by advanced approximations to the exchange-correlation (XC)…

Strongly Correlated Electrons · Physics 2018-07-16 Maria Hellgren

We propose a method for the evaluation of magnetic exchange couplings based on noncollinear spin-density functional calculations. The method employs the second derivative of the total Kohn-Sham energy of a single reference state, in…

Materials Science · Physics 2009-11-13 Juan E. Peralta , Veronica Barone

The exact universal functional of integer charge leads to an extension to fractional charge asymptotically when it is applied to a system made of asymptotically separated densities. The extended functional is asymptotically local and is…

Chemical Physics · Physics 2024-12-17 Jing Kong

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

Density functional theory (DFT) is one of the most widely used tools to solve the many-body Schrodinger equation. The core uncertainty inside DFT theory is the exchange-correlation (XC) functional, the exact form of which is still unknown.…

Computational Physics · Physics 2019-10-15 Alexander Ryabov , Iskander Akhatov , Petr Zhilyaev

Noncollinear magnets are notoriously difficult to describe within first-principles approaches based on density-functional theory (DFT) because of the presence of low-lying spin excitations. At the level of ground-state calculations, several…

Materials Science · Physics 2026-03-09 Miquel Royo , Massimiliano Stengel

Spin-dependent exchange-correlation energy functionals in use today depend on the charge density and the magnetization density: $E_{\rm xc}[\rho,{\bf m}]$. However, it is also correct to define the functional in terms of the curl of ${\bf…

Other Condensed Matter · Physics 2017-04-18 S. Sharma , E. K. U. Gross , A. Sanna , J. K. Dewhurst