Condensed Matter Theory, National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
Scientific Computing Department, Materials Science and Engineering, Florida State University, Tallahassee, Florida 32310, USA.
J Chem Phys. 2018 Feb 14;148(6):064707. doi: 10.1063/1.5008996.
Bilayer graphene (BLG) is a semiconductor whose band gap and properties can be tuned by various methods such as doping or applying gate voltage. Here, we show how to tune electronic properties of BLG by intercalation of transition metal (TM) atoms between two monolayer graphene (MLG) using a novel dispersion-corrected first-principle density functional theory (DFT) approach. We intercalated V, Nb, and Ta atoms between two MLG. We found that the symmetry, the spin, and the concentration of TM atoms in BLG-intercalated materials are the important parameters to control and to obtain a Dirac cone in their band structures. Our study reveals that the BLG intercalated with one vanadium (V) atom, BLG-1V, has a Dirac cone at the K-point. In all the cases, the present DFT calculations show that the 2p sub-shells of C atoms in graphene and the 3d sub-shells of the TM atoms provide the electron density near the Fermi energy level (E) which controls the material properties. Thus, we show that out-of-plane atoms can influence in-plane electronic densities in BLG and enumerate the conditions necessary to control the Dirac point. This study offers insight into the physical properties of 2D BLG intercalated materials and presents a new strategy for controlling the electronic properties of BLG through TM intercalation by varying the concentration and spin arrangement of the metals resulting in various conducting properties, which include: metal, semi-metal and semiconducting states.
双层石墨烯（BLG）是一种半导体，其带隙和性质可以通过各种方法（如掺杂或施加栅极电压）进行调节。在这里，我们展示了如何通过在两层单层石墨烯（MLG）之间插入过渡金属（TM）原子来调节 BLG 的电子性质，使用了一种新颖的基于色散校正的第一性原理密度泛函理论（DFT）方法。我们在两层 MLG 之间插入了 V、Nb 和 Ta 原子。我们发现，BLG 插层材料中 TM 原子的对称性、自旋和浓度是控制和获得其能带结构中狄拉克锥的重要参数。我们的研究表明，插入一个钒（V）原子的 BLG，即 BLG-1V，在 K 点具有狄拉克锥。在所有情况下，目前的 DFT 计算表明，石墨烯中 C 原子的 2p 亚壳层和 TM 原子的 3d 亚壳层在费米能级（E）附近提供了电子密度，控制着材料的性质。因此，我们表明，面外原子可以影响 BLG 中的面内电子密度，并列举了通过改变金属的浓度和自旋排列来控制 BLG 电子性质的必要条件，从而产生各种导电性质，包括：金属、半金属和半导体状态。
