Atomistic Hartree theory of twisted double bilayer graphene near the magic angle
Atomistic Hartree theory of twisted double bilayer graphene near the magic angle
复制标题
魔角附近扭曲双双层石墨烯的原子Hartree理论
DOI：
10.1088/2516-1075/ac5eaa
复制
发表时间：
2022
影响因子：
2.6
通讯作者：
Cheung C
中科院分区：
文献类型：
--
作者：
Cheung C
扭曲双层石墨烯（tDBLG）是一种莫尔材料，最近由于在魔角附近观察到相关相位而引起了人们的极大兴趣。我们进行原子Hartree理论计算，研究电子-电子相互作用的作用，在正常状态的tDBLG。与扭曲的双层石墨烯相反，我们发现这种相互作用不会导致tDBLG的电子能带结构发生显著的掺杂依赖性变形。然而，相互作用在垂直电场的存在下对电子结构起着重要的作用，因为它们屏蔽了外部电场。最后，我们分析了Hartree势对晶体场的贡献，即内外层之间的在位能量差。我们发现，从Hartree理论获得的现场能量具有相同的符号，但较小的幅度相比，在以前的研究中，现场能量是通过拟合紧束缚的结果从头算密度泛函理论（DFT）带结构。为了理解这种定量差异，我们分析了从头算Kohn-Sham势从DFT得到的，发现一个微妙的相互作用的电子-电子和电子-离子相互作用决定了现场电位的大小。
Twisted double bilayer graphene (tDBLG) is a moiré material that has recently generated significant interest because of the observation of correlated phases near the magic angle. We carry out atomistic Hartree theory calculations to study the role of electron–electron interactions in the normal state of tDBLG. In contrast to twisted bilayer graphene, we find that such interactions do not result in significant doping-dependent deformations of the electronic band structure of tDBLG. However, interactions play an important role for the electronic structure in the presence of a perpendicular electric field as they screen the external field. Finally, we analyze the contribution of the Hartree potential to the crystal field, ie the on-site energy difference between the inner and outer layers. We find that the on-site energy obtained from Hartree theory has the same sign, but a smaller magnitude compared to previous studies in which the on-site energy was determined by fitting tight-binding results to ab initio density-functional theory (DFT) band structures. To understand this quantitative difference, we analyze the ab initio Kohn–Sham potential obtained from DFT and find that a subtle interplay of electron–electron and electron–ion interactions determines the magnitude of the on-site potential.
影响因子：
5.7
作者：
Fischer, Ammon;Goodwin, Zachary A. H.;Klebl, Lennart
通讯作者：
Klebl, Lennart