Developing alternative paradigms of electronics beyond silicon technology requires the exploration of fundamentally new physical mechanisms, such as the valley specific phenomena in hexagonal two-dimensional materials. We realize ballistic valley Hall kink states in bilayer graphene and demonstrate gate-controlled current transmission in a four-kink router device. The operations of a waveguide, a valve and a tunable electron beam splitter are demonstrated. The valley valve exploits the valley-momentum locking of the kink states and reaches an on/off ratio of 8 at zero magnetic field. A magnetic field enables a full-ranged tunable coherent beam splitter. These results pave the path to building a scalable, coherent quantum transportation network based on the kink states.
@article{arxiv.1708.02311,
title = {A valley valve and electron beam splitter},
author = {Jing Li and Rui-Xing Zhang and Zhenxi Yin and Jianxiao Zhang and Kenji Watanabe and Takashi Taniguchi and Chaoxing Liu and Jun Zhu},
journal= {arXiv preprint arXiv:1708.02311},
year = {2018}
}