论文标题
石墨烯中光诱导的非扰动谷极化
Photoinduced Nonperturbative Valley Polarization in Graphene
论文作者
论文摘要
我们研究了基于石墨烯的valleytronic设备，并在不同的sublattices处进行了电荷分离，并在非较少山谷处相应地进行了分离。我们表征了山谷极化的最大条件，并研究了我们可以通过山谷自由度一致控制载体和存储数据的参数和条件。山谷极化受脉冲的振幅以及载体包络相控制，以及互惠空间中电子轨迹的曲率。当考虑强场激发时，扰动光学元件中的光学选择规则将被非绝热的几何效应取代。结果，无论具有固有的带隙，都会引起二维迪拉克材料中的非驱动谷极化。从显微镜上讲，手性电场中石墨烯的这种非转化反应由量子浆果相编码，作为（伪）磁电单极。
We investigate a valleytronic device based on graphene with charge separation at different sublattices and correspondingly at nonequivalent valleys. We characterize the maximality condition of valley polarization and investigate the parameters and conditions upon which we can coherently control the carriers and store data via valley degree of freedom. The valley polarization is controlled by the amplitude as well as the carrier envelope phase of the pulse and the curvature of the electron trajectory in the reciprocal space. When strong field excitation is taken into account, the optical selection rule in perturbative optics is replaced by the nonadiabatic geometric effects. As a result, a nonperturbative valley polarization in two dimensional Dirac materials is induced regardless of having an intrinsic bandgap. Microscopically, such a nonreciprocal response of graphene in the chiral electric field is encoded by the quantum Berry phase, as a (pseudo) magnetoelectric monopole.
