Ballistic conductivity of graphene channel with p-n junction at ferroelectric domain wall

Abstract

The influence of a ferroelectric domain wall on the ballistic conductance of a single-layer graphene channel in the graphene/physical gap/ferroelectric film heterostructure has been studied in the Wentzel-Kramers-Brillouin approximation. The self-consistent numerical simulation of the electric field and the space charge dynamics in the heterostructure, as well as the approximate analytical theory, show that the contact between the domain wall and the surface creates a p-n junction in the graphene channel. We calculated that the carrier concentration induced in graphene by uncompensated ferroelectric dipoles originated from the abrupt spontaneous polarization change near the surface can reach values of about 1019 m−2, which are two orders of magnitude higher than those obtained for the graphene on non-ferroelectric substrates. Therefore, we predict that the graphene channel with the p-n junction caused by the ferroelectric domain wall would be characterized by rather a high ballistic conductivity. Moreover, the graphene p-n junction at the ferroelectric domain wall can be an excellent rectifier with a conductivity ratio of about 10 between the direct and reverse polarities of the applied voltage.