标题： 由掺杂石墨烯中扩展的排斥相互作用驱动的自旋键序 显示英文标题

标题： Spin bond order driven by extended repulsive interactions in doped graphene

摘要： 我们使用截断单位函数重整化群（TUFRG）来研究掺杂接近范霍夫奇点（VHS）的石墨烯中关联电子的多体不稳定性。 该系统由一个扩展的哈伯德模型描述，包括相邻位点之间的多种库仑排斥。 通过适合于石墨烯低能考虑的排斥参数，我们在VHS附近发现了一种自旋键序相。 当引入弱额外屏蔽时，该相会转变为自旋密度波相。 在掺杂水平和屏蔽参数的空间中给出了基态相图。 我们详细描述了这两种自旋有序态，使用了最近开发的TUFRG + MF方案，即TUFRG和平均场（MF）理论的结合方法。 在自旋键序和自旋密度波的情况下，共线态在能量上更优。 但如果缺少第三近邻跃迁，则这些自旋序变为手性的。 给出了两种共线自旋有序态的能带结构，揭示了系统的金属行为。 显示英文摘要

摘要： We use the truncated-unity functional renormalization group (TUFRG) to study many-body instabilities of correlated electrons in graphene doped near the van Hove singularity (VHS). The system is described by an extended Hubbard model including several Coulomb repulsions between neighboring sites. With the repulsion parameters, which turn out to be suitable for low-energy consideration of graphene, we find a spin-bond-order phase in the vicinity of the VHS. This phase gives way to a spin-density-wave phase when involving a weak additional screening. The ground-state phase diagram is presented in the space of the doping level and the screening parameter. We describe in detail both of these spin-ordered states by using recently developed TUFRG + MF scheme, i.e., a combined approach of TUFRG and mean-field (MF) theory. The collinear states are energetically preferable in both cases of the spin bond order and the spin-density wave. But if the third-nearest-neighbor hopping is absent, these spin orders become chiral. The band structures of two collinear spin-ordered states are presented, revealing the metallic behavior of the system.