Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany.
Phys Rev Lett. 2013 Jul 19;111(3):036601. doi: 10.1103/PhysRevLett.111.036601. Epub 2013 Jul 16.
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.
为了理解非局域库仑相互作用如何影响关联电子材料的相图，我们报告了一种通过有效 Hubbard 模型（仅具有局域相互作用 U()）来近似具有非局域相互作用的关联晶格模型的方法。有效模型由 Peierls-Feynman-Bogoliubov 变分原理定义。我们发现，相互作用 U 的局域部分根据 U() = U - V[over ¯] 减小，其中 V[over ¯] 是非局域相互作用的加权平均值。对于石墨烯、硅烯和苯，我们表明，在宽掺杂范围内，非局域库仑相互作用可以使有效局域相互作用降低 2 倍以上。
