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It has been known for some time that the exchange-correlation potential in time-dependent density functional theory is an intrinsically nonlocal functional of the density as soon as one goes beyond the adiabatic approximation. In this paper…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Z. Qian , A. Constantinescu , G. Vignale

We study spin polarization in a split-gate quantum wire focussing on the effect of a realistic smooth potential due to remote donors. Electron interaction and spin effects are included within the density functional theory in the local spin…

Mesoscale and Nanoscale Physics · Physics 2008-04-04 M. Evaldsson , S. Ihnatsenka , I. V. Zozoulenko

We review and expand on our work to impose constraints on the effective Kohn Sham (KS) potential of local and semi-local density functional approximations. In this work, we relax a previously imposed positivity constraint, which increased…

The density functional theory (DFT) is a remarkably successful theory of electronic structure of matter. At the foundation of this theory lies the Kohn-Sham (KS) equation. In this paper, we describe the long-time behaviour of the…

Analysis of PDEs · Mathematics 2021-05-11 Fabio Pusateri , Israel Michael Sigal

The exact conditions for density functionals and density matrix functionals in terms of fractional charges and fractional spins are known, and their violation in commonly used functionals has been shown to be the root of many major failures…

Other Condensed Matter · Physics 2015-06-16 Weitao Yang , Paula Mori-Sanchez , Aron J. Cohen

A fundamental weakness of density functional theory (DFT) is the difficulty in making systematic improvements to approximations for the exchange and correlation functionals. In this paper, we follow a wave-function-based approach [N.I.…

Chemical Physics · Physics 2018-10-05 Timothy J. Callow , Nikitas I. Gidopoulos

Dynamical correlations of the spin and the energy density are investigated in the critical region of the random transverse-field Ising chain by numerically exact calculations in large finite systems (L<=128). The spin-spin autocorrelation…

Disordered Systems and Neural Networks · Physics 2016-08-31 H. Rieger , F. Igloi

We propose a model to explore the dynamics of spin-systems coupled by exchange interaction to the conduction band electrons of a semiconductor material that forms the channel in a ferromagnet/semiconductor/ferromagnet spin-valve structure.…

Mesoscale and Nanoscale Physics · Physics 2008-11-04 L. Siddiqui , D. Saha , S. Datta , P. Bhattacharya

It is shown here that Kohn-Sham equations cannot be derived from Hohenberg-Kohn theory without an additional postulate. Assuming that a functional derivative with respect to total electron density exists leads in general to a theory…

Condensed Matter · Physics 2007-05-23 R. K. Nesbet

Antiferromagnets are promising candidates as active components in spintronic applications. They share features with ferrimagnets in that opposing spin orientations exist in two or more sublattices. Spin transfer torque and spin pumping are…

Mesoscale and Nanoscale Physics · Physics 2024-09-24 Hans Gløckner Giil , Arne Brataas

Using an end-to-end differentiable implementation of the Kohn-Sham self-consistent field equations, we obtain an accurate neural network-based exchange and correlation (XC) functional of the electronic density. The functional is optimized…

Chemical Physics · Physics 2021-06-09 Sebastian Dick , Marivi Fernandez-Serra

Simulations in the warm dense matter regime using finite temperature Kohn-Sham density functional theory (FT-KS-DFT), while frequently used, are computationally expensive due to the partial occupation of a very large number of high-energy…

Materials Science · Physics 2018-04-04 Yael Cytter , Eran Rabani , Daniel Neuhauser , Roi Baer

Exchange interactions are a manifestation of the quantum mechanical nature of the electrons and play a key role in predicting the properties of materials from first principles. In density functional theory (DFT), a widely used approximation…

Materials Science · Physics 2020-03-27 Marco Bernardi

We investigate coherent transport through open lateral quantum dots using recursive Green's function technique, incorporating exchange-correlation effects within local spin-density approximation (LSDA). At low electron densities the current…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 M. Evaldsson , I. V. Zozoulenko

We introduce a novel energy functional for ground-state electronic-structure calculations. Its fundamental variables are the natural spin-orbitals of the implied singlet many-body wave function and their joint occupation probabilities. The…

Chemical Physics · Physics 2015-06-23 Ralph Gebauer , Morrel H. Cohen , Roberto Car

The spin structure in a magnetic dot, which is an example of a quantum few-body system, is studied as a function of exchange coupling strength and dot size with in the semiclassical approximation on a discrete lattice. As the exchange…

Other Condensed Matter · Physics 2009-11-11 Mohammad-Reza Mozaffari , Keivan Esfarjani

We study ferromagnetic transition in three-dimensional double-exchange model. The influence of strong spin fluctuations on conduction electrons is described in coherent potential approximation. In the framework of thermodynamic approach we…

Statistical Mechanics · Physics 2013-05-29 Mark Auslender , Eugene Kogan

Exchange-correlation potentials vxc and energy densities exc are derived for integer and fractional electron counts using an orbital-averaged Kohn-Sham inversion procedure. The reference densities for inversion come from full configuration…

Chemical Physics · Physics 2025-04-30 Vaibhav Khanna , Bikash Kanungo , Jeffrey Hatch , Joshua Kammeraad , Paul M. Zimmerman

A systematic comparative study has been performed to better understand DFT$+U$ (density functional theory + $U$) method. We examine the effect of choosing different double counting and exchange-correlation functionals. The calculated energy…

Strongly Correlated Electrons · Physics 2018-06-26 Siheon Ryee , Myung Joon Han

We propose exchanging the energy functionals in ground-state DFT with physically equivalent exact force expressions as a new promising route towards approximations to the exchange-correlation potential and energy. In analogy to the usual…