Effects Of Intervalley Scattering On The Transport Properties In One-Dimensional Valleytronic Devices

In recent years, the community have generated extensive interest in manipulating and controlling of valley, which is a new degree of freedom of the charge carriers, and thus stimulate a blooming field of valleytronics. Here, we begin with constructing a one-dimensional lattice model and address such an issue on the basis of investigating the valley transport properties in this valley material junction devices.We assume that the electron hopping in the lattice can only happen between the S orbit and the nearest-neighbor site Px orbits. And then, we can get two inequivalent valley K and K’ in momentum space and the modes of their wave functions by the means of tight-binding representation. Considering the continuity relationship of wave function in the interface, the corresponding transmission and reflection probabilities can be calculated. In this case, valley-related coefficients can be studied numerically and their influences of valley transport in the interface can be figured out.The following discussion about the transport properties of valley junction will be divided into three parts: 1) gapless junction between two gapless valley materials( 0L R? ? ? ?); 2) hybridized junction with gapless and gapped valley materials( 0, 0L R? ? ? ? or 0, 0L R? ? ? ?); 3) gapped junction between two gapped valley materials( 0, 0L R? ? ? ?). Our analytic results have clearly shown that the carriers have strong intervalley scattering in the interface of the junction, which can greatly influence the valley transport properties of valleytronic devices. Concretely, for a junction with two gapless valley materials, the intervalley scattering can cause the reflection of the tunneling carriers and damage the perfect tunneling. Nevertheless, the valley polarization of the carriers remians unchanged in such a case. In contrast, for a junction containing gapped valley materials, the valley polarization of the carriers can be changed during the tunneling process. Besides, we discover a valley polarization resonance phenomena and extract the corresponding condition, which may be utilized to manipulate the valley degree in the future.