Band structure engineering and transport properties of graphene/BN van der Waals heterostructures

It is an important topic in spintronics to find regulable half-metallic materials. In this work, by using density functional theory and nonequilibrium Green’s functional method, we find that the van der Waals heterostructures formed by zigzag-edged boron nitride nanoribbons and zigzag-edged graphene nanoribbons (ZGNRs) are spin splitting semiconductors. The energy band gap of the heterostructures can be regulated by applying a local voltage and the semiconductor–metal–semiconductor phase transition can be realized. Two spin-dependent transport devices are constructed based on the heterostructures. One device can generate a fully spin-polarized current within a small bias range, and the other device can generate high spin polarization within a large bias range. Moreover, based on zigzag-edged graphene/boron nitride nanoribbon (ZGBNNR) heterostructures, a dual-probe device with double vertical gates in the electrode regions is designed, which can form a metal–semiconductor–metal tunneling device. These findings indicate that ZGBNNRs can be used in excellent spintronic devices.