Strong correlations in density-functional theory: A model of spin-charge and spin-orbital separations
Abstract
It is known that the separation of electrons into spinons and chargons, the spin-charge separation, plays a decisive role when describing strongly correlated density distributions in one dimension. In this manuscript, we extend the investigation by considering a model for the third electron fractionalization: the separation into spinons, chargons and orbitons -- the last associated with the electronic orbital degree of freedom. Specifically, we deal with two exact constraints of exchange-correlation (XC) density-functionals: (i) The constancy of the highest occupied (HO) Kohn-Sham (KS) eigenvalues upon fractional electron numbers, and (ii) their discontinuities at integers. By means of one-dimensional (1D) discrete Hubbard chains and 1D Hydrogen molecules in the continuum, we find that spin-charge separation yields almost constant HO KS eigenvalues, whereas the spin-orbital counterpart can be decisive when describing derivative discontinuities of XC potentials at strong correlations.
Keywords
Cite
@article{arxiv.1212.3241,
title = {Strong correlations in density-functional theory: A model of spin-charge and spin-orbital separations},
author = {Daniel Vieira},
journal= {arXiv preprint arXiv:1212.3241},
year = {2014}
}