论文标题
在ABC Trilayer石墨烯中，方向控制的化学掺杂用于可逆的G-Phonon混合
Direction-Controlled Chemical Doping for Reversible G-Phonon Mixing in ABC Trilayer Graphene
论文作者
论文摘要
不仅明显的原子布置，而且电荷分布还定义了决定电子和振动结构的晶体对称性。在这项工作中，我们报告了可逆和方向控制的化学掺杂，从而改变了AB-Bilayer和Abctrilayer石墨烯的反转对称性。对于上向下和自下而上的孔注射到石墨烯片中，我们分别采用了电负性I2和退火诱导的界面孔掺杂的分子吸附。反转对称的化学分解导致G声子，拉曼活性EG和拉曼不活跃的欧盟模式的混合，这表现为两个分裂的G峰，G-和G+。可以通过简单的冲洗或界面分子替换来消除孔掺杂剂来恢复损坏的反变对称性。另外，可以通过双侧电荷注入来恢复对称性，从而消除了g-并形成了一个额外的峰，该峰源自几乎没有掺杂的内部层。当前研究中所证明的晶体对称性的化学修饰可以应用于其他低维晶体，以调整其各种材料特性。
Not only the apparent atomic arrangement but the charge distribution also defines the crystalline symmetry that dictates the electronic and vibrational structures. In this work, we report reversible and direction-controlled chemical doping that modifies the inversion symmetry of AB-bilayer and ABCtrilayer graphene. For the top-down and bottom-up hole injection into graphene sheets, we employed molecular adsorption of electronegative I2 and annealing-induced interfacial hole doping, respectively. The chemical breakdown of the inversion symmetry led to the mixing of the G phonons, Raman active Eg and Raman-inactive Eu modes, which was manifested as the two split G peaks, G- and G+. The broken inversion symmetry could be recovered by removing the hole dopants by simple rinsing or interfacial molecular replacement. Alternatively, the symmetry could be regained by double-side charge injection, which eliminated G- and formed an additional peak, Go, originating from the barely doped interior layer. Chemical modification of crystalline symmetry as demonstrated in the current study can be applied to other low dimensional crystals in tuning their various material properties.
