超胞万尼尔函数与伯纳尔双层石墨烯的忠实低能模型
Supercell Wannier functions and a faithful low-energy model for Bernal bilayer graphene
AI总结：
本研究通过构建超胞万尼尔轨道推导伯纳尔双层石墨烯及相关多层膜的最小低能模型，再现微观模型关键性质并揭示低能物理机制，架起连续介质理论与从头算研究的桥梁。
摘要：
我们通过构建原始原胞实空间超胞中定义的万尼尔轨道，推导了低电子密度下伯纳尔双层石墨烯及相关菱面体石墨烯多层膜的最小低能模型。从包含碳原子p_z轨道的从头算电子结构理论出发，通过将π能带折叠到超胞伴随的迷你布里渊区，规避了K、K'点附近费米表面口袋的动量局域性，这让人联想到它们的（扭曲）莫尔对应物。超胞万尼尔函数再现了微观模型的谱权重和贝里曲率，并提供了直观的实空间图像：低电子密度下的涌现物理由具有介观尺度的味极化波包塑造。通过将轨道分辨的双栅极库仑相互作用投影到有效万尼尔基上，我们发现伯纳尔双层石墨烯的低能物理由弱电子-电子相互作用主导。本研究通过对低能物理提供对称晶格描述，在现有连续介质理论与菱面体石墨烯堆叠等小费米口袋系统的从头算研究之间架起了桥梁。
英文摘要：
We derive a minimal low-energy model for Bernal bilayer graphene and related rhombohedral graphene multilayers at low electronic densities by constructing Wannier orbitals defined in real-space supercells of the original primitive cell. Starting from an ab-initio electronic structure theory comprising the atomic carbon $p_z$-orbitals, momentum locality of the Fermi surface pockets around $K,K'$ is circumvented by backfolding the $π$-bands to the concomitant mini-Brillouin zone of the supercell, reminiscent of their (twisted) moiré counterparts. The supercell Wannier functions reproduce the spectral weight and Berry curvature of the microscopic model and offer an intuitive real-space picture of the emergent physics at low electronic densities being shaped by flavor-polarized wave packets with mesoscopic extent. By projecting an orbital-resolved, dual-gated Coulomb interaction to the effective Wannier basis, we find that the low-energy physics of Bernal bilayer graphene is governed by weak electron-electron interactions. Our study bridges between existing continuum theories and ab-initio studies of small Fermi pocket systems like rhombohedral graphene stacks by providing a symmetric lattice description of their low-energy physics.
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