Valley splitting and anomalous Klein tunneling in borophane-based n-p and n-p-n junctions

摘要

We analytically investigate the transport properties of electron in borophane-based n-p and n-p-n junctions. When the electron beam in n region go through the n-p junction, the beam will be split into two valley-dependent beam in p region. This comes from the valley-dependent refraction angle induced by the anisotropic band structure of borophane. Interestingly, the behavior of valley splitting can be generated in a borophane-based n-p junction naturally without any external modulation methods. Generally, the Klein tunneling is described as the perfect transmission at a zero incident angle of electron regardless of the width and height of potential barrier. However, in a borophane-based n-p-n junction, the anomalous Klein tunneling, i.e., the perfect transmission exists at a nonzero incident angle, is found due to the anisotropic band structure of borophane. Our work designs an alternative valley splitter and provides an insight into the understanding of the Klein tunneling. (C) 2020 Elsevier B.V. All rights reserved.