文章基本信息

标题：Exact exchange-correlation potential of an ionic Hubbard model with a free surface
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作者：V. Brosco ; Z.-J. Ying ; J. Lorenzana 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2013
卷号：3
期号：1
DOI：10.1038/srep02172
语种：English
出版社：Springer Nature
摘要：In Kohn-Sham density functional theory (DFT) the interacting electron problem is mapped into a noninteracting problem in an effective potential v_KS . It is known that the charge gap of the interacting system is different from the gap of the effective problem due to a jump Δ _xc in v_KS when an electron is added but its magnitude and its role in the ubiquitous discrepancy between the experimental gaps and approximate DFT computations is poorly understood. Here we compute the exact v_KS of a strongly interacting one-dimensional lattice model which can be driven from an ionic to a Mott insulating state. Presence of a “vacuum” region allows to determine the absolute value of v_KS . We show that in the ionic regime Δ _xc is determined by nearest-neighbor interaction, while in the Mott regime Δ _xc is determined by on-site Hubbard interaction.