It is a persisting pursuit to use metal as a channel material in a fieldeffect transistor. All metallic transistor can be fabricated from pristinesemimetallic Dirac materials (such as graphene, silicene, and germanene), butthe on/off current ratio is very low. In a vertical heterostructure composed bytwo Dirac materials, the Dirac cones of the two materials survive the weakinterlayer van der Waals interaction based on density functional theory method,and electron transport from the Dirac cone of one material to the one of theother material is therefore forbidden without assistance of phonon because ofmomentum mismatch. First-principles quantum transport simulations of theall-metallic vertical Dirac material heterostructure devices confirm theexistence of a transport gap of over 0.4 eV, accompanied by a switching ratioof over 104. Such a striking behavior is robust against the relative rotationbetween the two Dirac materials and can be extended to twisted bilayergraphene. Therefore, all-metallic junction can be a semiconductor and novelavenue is opened up for Dirac material vertical structures in high-performancedevices without opening their band gaps.
展开▼
