标题： 硼和氮掺杂的石墨烯双层中的电场效应 显示英文标题

标题： Electric field effect in boron and nitrogen doped graphene bilayers

摘要： 与单层石墨烯不同，在$AB$堆叠的双层石墨烯（BLG）情况下，可以通过使用垂直电场打破两层之间的反演对称性来诱导非零能隙。这是场效应应用中的基本要求，特别是因为BLG系统中诱导的能隙可以通过外加电场的大小进一步调节。掺杂是另一种修改基于石墨烯系统电子性质的方法。我们在此研究了在外部电场存在下，硼和氮掺杂的BLG系统，在密度泛函理论（DFT）计算框架下。高度掺杂的BLG系统已知表现出简并半导体的行为，其中费米能级取决于掺杂浓度，但除此之外，我们还表明电子性质也显著依赖于所施加的电场。通过改变电场的大小和方向，能隙大小及其相对于费米能级的位置可以被调节，从而基本上控制外源掺杂的效果。在此背景下，我们讨论外部电场在多大程度上可以适当调整有效掺杂，从而影响掺杂BLG系统的导电性质。 显示英文摘要

摘要： Unlike single layer graphene, in the case of $AB$-stacked bilayer graphene (BLG) one can induce a non-zero energy gap by breaking the inversion symmetry between the two layers using a perpendicular electric field. This is an essential requirement in field-effect applications, particularly since the induced gap in BLG systems can be further tuned by the magnitude of the external electric field. Doping is another way to modify the electronic properties of graphene based systems. We investigate here BLG systems doped with boron and nitrogen in the presence of external electric field, in the framework of density functional theory (DFT) calculations. Highly doped BLG systems are known to behave as degenerate semiconductors, where the Fermi energy depends on the doping concentration but, in addition, we show that the electronic properties drastically depend also on the applied electric field. By changing the magnitude and the orientation of the electric field, the gap size and position relative to the Fermi level may be tuned, essentially controlling the effect of the extrinsic doping. In this context, we discuss in how far the external electric field may suitably adjust the effective doping and, implicitly, the conduction properties of doped BLG systems.