Density functional theory was used to investigate the geometric structure of bilayer graphene under an external electric field with carrier doping. Our calculations revealed the crucial impact of external electric fields and the hole injection on determining the geometric structure of bilayer graphene. The bond length of graphene monotonically increased when increasing the hole doping concentration, while it remained insensitive to electron doping. Additionally, there accumulated carriers predominantly distributed in the outermost layer located just below the gate electrode. These results enabled the construction of moiré superlattices in the bilayer graphene, possessing different moiré periodicity depending on the carrier concentration.

中文翻译：

---

外电场和载流子掺杂下双层石墨烯的结构调制

利用密度泛函理论研究了载流子掺杂的外电场下双层石墨烯的几何结构。我们的计算揭示了外部电场和空穴注入对确定双层石墨烯几何结构的关键影响。当空穴掺杂浓度增加时，石墨烯的键长单调增加，而对电子掺杂不敏感。另外，积累的载流子主要分布在位于栅电极正下方的最外层中。这些结果使得能够在双层石墨烯中构建莫尔超晶格，根据载流子浓度具有不同的莫尔周期性。