Xiao Di, Yao Wang, Niu Qian
Department of Physics, The University of Texas, Austin, Texas 78712-0264, USA.
Phys Rev Lett. 2007 Dec 7;99(23):236809. doi: 10.1103/PhysRevLett.99.236809.
We investigate physical properties that can be used to distinguish the valley degree of freedom in systems where inversion symmetry is broken, using graphene systems as examples. We show that the pseudospin associated with the valley index of carriers has an intrinsic magnetic moment, in close analogy with the Bohr magneton for the electron spin. There is also a valley dependent Berry phase effect that can result in a valley contrasting Hall transport, with carriers in different valleys turning into opposite directions transverse to an in-plane electric field. These effects can be used to generate and detect valley polarization by magnetic and electric means, forming the basis for the valley-based electronics applications.
我们以石墨烯系统为例,研究在反演对称性被打破的系统中可用于区分谷自由度的物理性质。我们表明,与载流子谷指数相关的赝自旋具有本征磁矩,这与电子自旋的玻尔磁子非常类似。还存在一种依赖于谷的贝里相位效应,它可导致谷对比霍尔输运,不同谷中的载流子在垂直于面内电场的方向上转向相反方向。这些效应可用于通过磁和电手段产生和检测谷极化,构成基于谷的电子学应用的基础。