Effect of the Electrostatic Barrier on the Valley Polarization in a Graphene

Valleytronic device based on graphene is recently attracting growing interest because of its potential applications such as in quantum information storage and transmission. However, one of the major challenges in designing valleytronic devices is to realize the large valley polarization. Therefore, in the present work, we investigate the effect of the electrostatic barrier on the valley polarization in a graphene modulated by two ferromagnetic metal stripes and one strain, where the large valley polarization can be achieved due to the effect of the electrostatic barrier. With the increase in the height or the width of the electrostatic barrier, the degree of the valley polarization will greatly increase. These interesting finds are very helpful for understanding the valley-dependent transport mechanism of electrons in graphene and designing the valleytronic devices based on graphene under the modulation of the electrostatic barrier.