Optimal Hubbard models for materials with nonlocal Coulomb interactions: graphene, silicene, and benzene

To understand how nonlocal Coulomb interactions affect the phase diagram of correlated electron materials, we report on a method to approximate a correlated lattice model with nonlocal interactions by an effective Hubbard model with on-site interactions U(*) only. The effective model is defined by t...

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Bibliographic Details
Published in:Physical review letters 2013-07, Vol.111 (3), p.036601-036601, Article 036601
Main Authors: Schüler, M, Rösner, M, Wehling, T O, Lichtenstein, A I, Katsnelson, M I
Format: Article
Language:English
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Summary:To understand how nonlocal Coulomb interactions affect the phase diagram of correlated electron materials, we report on a method to approximate a correlated lattice model with nonlocal interactions by an effective Hubbard model with on-site interactions U(*) only. The effective model is defined by the Peierls-Feynman-Bogoliubov variational principle. We find that the local part of the interaction U is reduced according to U(*)=U-V[over ¯], where V[over ¯] is a weighted average of nonlocal interactions. For graphene, silicene, and benzene we show that the nonlocal Coulomb interaction can decrease the effective local interaction by more than a factor of 2 in a wide doping range.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.111.036601