论文标题
扭曲的双层石墨烯中的Minivalley和层控制
Combined minivalley and layer control in twisted double bilayer graphene
论文作者
论文摘要
对Minivalley偏振和层间耦合的控制在双重双层石墨烯中证明，角度为2.37 $^\ Circ $。该中间角度足够小，以使小型型形成形成和足够大，以使层中的电荷载体气体可以独立调整。使用双门控几何形状，我们通过两个双层的种群来识别和控制Minivalley极化的所有可能组合。施加的位移场在两个双层中的任何一个中都打开了带隙，从而使我们甚至获得了全米瓦利极化。另外，小型莱顿的波形通过通过Lifshitz Transition进行调整而混合，那里的Fermi表面拓扑会发生变化。高度的控制使扭曲的双重双层石墨烯成为山谷阀，滤波器和逻辑大门等山谷设备的有前途的平台。
Control over minivalley polarization and interlayer coupling is demonstrated in double bilayer graphene twisted with an angle of 2.37$^\circ$. This intermediate angle is small enough for the minibands to form and large enough such that the charge carrier gases in the layers can be tuned independently. Using a dual-gated geometry we identify and control all possible combinations of minivalley polarization via the population of the two bilayers. An applied displacement field opens a band gap in either of the two bilayers, allowing us to even obtain full minivalley polarization. In addition, the wavefunctions of the minivalleys are mixed by tuning through a Lifshitz transition, where the Fermi surface topology changes. The high degree of control makes twisted double bilayer graphene a promising platform for valleytronics devices such as valley valves, filters and logic gates.
