Valley polarization in graphene-silicene-graphene heterojunction
  Considering the difference of energy bands in graphene and silicene, we put forward a new model of the graphene-silicene-graphene (GSG) heterojunction. In the GSG, we study the valley polarization properties in a zigzag nanoribbon in the presence of an external electric field. We find the energy range associated with the bulk gap of silicene has a valley polarization more than 95%. Under the protection of the topological edge states of the silicene, the valley polarization remains even the small non-magnetic disorder is introduced. These results have certain practical significance in applications for future valley valve. 
Man Shen, Yan-Yang Zhang, Xing-Tao An, Jian-Jun Liu, and Shu-Shen Li
cond-mat.mes-hall cond-mat.str-el