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We construct a generalized-gradient approximation for the exchange-energy density of finite two-dimensional systems. Guided by non-empirical principles, we include the proper small-gradient limit and the proper tail for the exchange-hole…

Strongly Correlated Electrons · Physics 2014-03-26 J. G. Vilhena , E. Rasanen , M. A. L. Marques , S. Pittalis

Commonly used semilocal density functional approximations for the exchange-correlation energy fail badly when the true two dimensional limit is approached. We show, using a quasi-two-dimensional uniform electron gas in the infinite barrier…

Materials Science · Physics 2015-05-13 Lucian A. Constantin

We extend the Becke-Johnson approximation [J. Chem. Phys. 124, 221101 (2006)] of the exchange potential to two dimensions. We prove and demonstrate that a direct extension of the underlying formalism may lead to divergent behavior of the…

Strongly Correlated Electrons · Physics 2010-04-08 S. Pittalis , E. Rasanen , C. R. Proetto

The exchange-correlation potential experienced by an electron in the free space adjacent to a solid surface or to a low-dimensional system defines the fundamental image states and is generally important in surface- and nano-science. Here we…

Mesoscale and Nanoscale Physics · Physics 2016-06-01 V. U. Nazarov

We present a practical and accurate density functional for the exchange-correlation energy of electrons in two dimensions. The exchange part is based on a recent two-dimensional generalized-gradient approximation derived by considering the…

Strongly Correlated Electrons · Physics 2010-06-30 E. Rasanen , S. Pittalis , J. G. Vilhena , M. A. L. Marques

We derive 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 not yet been…

Strongly Correlated Electrons · Physics 2009-01-07 S. Pittalis , E. Rasanen , J. G. Vilhena , M. A. L. Marques

Semi-local density functionals for the exchange-correlation energy of electrons are extensively used as it produce realistic and accurate results for finite and extended systems. The choice of techniques play crucial role in constructing…

Materials Science · Physics 2017-11-01 Subrata Jana , Prasanjit Samal

We investigate the behavior of three-dimensional (3D) exchange-correlation energy functional approximations of density functional theory in anisotropic systems with two-dimensional (2D) character. Using two simple models, quasi-2D electron…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Yong-Hoon Kim , In-Ho Lee , Satyadev Nagaraja , Jean-Pierre Leburton , Randolph Q. Hood , Richard M. Martin

We study the properties of the lower bound on the exchange-correlation energy in two dimensions. First we review the derivation of the bound and show how it can be written in a simple density-functional form. This form allows an explicit…

Strongly Correlated Electrons · Physics 2010-02-25 E. Rasanen , S. Pittalis , C. R. Proetto , K. Capelle

Most approximate exchange-correlation functionals used within density functional theory are constructed as the sum of two distinct contributions for exchange and correlation. Separating the exchange component from the entire functional is…

Condensed Matter · Physics 2009-10-28 Claudia Filippi , C. J. Umrigar , Xavier Gonze

We consider electronic exchange and correlation effects in density-functional calculations of two-dimensional systems. Starting from wave function calculations of total energies and electron densities of inhomogeneous model systems, we…

Mesoscale and Nanoscale Physics · Physics 2012-05-30 Ilja Makkonen , Mikko M. Ervasti , Ville Kauppila , Ari Harju

We present a new approach how to calculate the scalar exchange-correlation potentials and the vector exchange-correlation potentials from current-carrying ground states of two-dimensional quantum dots. From these exchange-correlation…

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

Semilocal exchange-correlation functionals are the most accurate, realistic and widely used ones to describe the complex many-electron effects of two-dimensional quantum systems. Beyond local density approximation, the generalized gradient…

Materials Science · Physics 2017-04-12 Subrata Jana , Prasanjit samal

We derive a local approximation for the correlation energy in two-dimensional electronic systems. In the derivation we follow the scheme originally developed by Colle and Salvetti for three dimensions, and consider a Gaussian approximation…

Strongly Correlated Electrons · Physics 2008-11-21 S. Pittalis , E. Rasanen , M. Marques

In order to assess the accuracy of commonly used approximate exchange-correlation density functionals, we present a comparison of accurate exchange and correlation potentials, exchange energy densities and energy components with the…

Condensed Matter · Physics 2007-05-23 Claudia Filippi , Xavier Gonze , C. J. Umrigar

We derive a two-term asymptotic expansion for the exchange energy of the free electron gas on strictly tessellating polytopes and fundamental domains of lattices in the thermodynamic limit. This expansion comprises a bulk (volume-dependent)…

Mathematical Physics · Physics 2025-03-24 Thiago Carvalho Corso

Aiming to remedy the incorrect asymptotic behavior of conventional semilocal exchange-correlation (XC) density functionals for finite systems, we propose an asymptotic correction scheme, wherein an exchange density functional whose…

Chemical Physics · Physics 2013-05-17 Chi-Ruei Pan , Po-Tung Fang , Jeng-Da Chai

The Becke-Johnson exchange potential [J. Chem. Phys. 124, 221101 (2006)] has been successfully used in electronic structure calculations within density-functional theory. However, in its original form the potential may dramatically fail in…

Materials Science · Physics 2010-01-28 E. Rasanen , S. Pittalis , C. Proetto

We calculate the exchange coupling for a double dot system using a novel, numerically exact yet efficient technique, based on finite-element methods. Specifically, we evaluate the exchange coupling both for a quasi-one and a two-dimensional…

Mesoscale and Nanoscale Physics · Physics 2007-10-03 Jesper Pedersen , Christian Flindt , Niels Asger Mortensen , Antti-Pekka Jauho

Electronic structure calculations are routinely carried out within the framework of density-functional theory, often with great success. For electrons in reduced dimensions, however, there is still a need for better approximations to the…

Strongly Correlated Electrons · Physics 2009-09-22 S. Pittalis , E. Rasanen , E. K. U. Gross
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