Directional quantum transport in graphyne p-n junction

Abstract

Graphyne, a newly proposed allotrope of carbon, has a structure which is topologically equivalent to that of a strongly distorted graphene [B. G. Kim and H. J. Choi, Phys. Rev. B 86, 115435 (2012)]. The energy gap between the valence and conduction bands is due to the symmetry breaking caused by there being three topologically inequivalent hoping elements. The valleyless fermionic transport properties of γ-graphyne are different from those of graphene since the two valleys are merged together in this carbon allotrope. The transmission and conductance of the electrons in γ-graphyne are found to be directionally dependent. Klein tunneling is predicted if the tunneling is in the y-direction. If the tunneling is in the x-direction, perfect back reflection (anti Klein tunneling) is predicted if the tunneling is at normal incidence. The consequences of these directional transport properties on the performances of p-n junctions fabricated with this carbon allotrope are studied. This work reveals the advantages of building p-n junctions based on γ-gaphyne. © 2013 American Institute of Physics.