Parity Effects Induced by the Resonant Electronic States Coupling in Polyacetylene-Based Devices

Abstract

The electronic transport properties of the carbon atomic chain in combination with a stand-up attached polyacetylene (C$_n$H$_n$ + 1) molecule sandwiched between two zigzag graphene nanoribbon electrodes, were investigated based on the density-function theory and the nonequilibrium Green's functions approach. Our calculation shows that the transport behavior is sensitive to the number of carbon atoms on the C$_n$H$_n$ + 1 chains. Specifically, we demonstrate that the transport properties of even-n C$_n$H$_n$ + 1 devices behave much stronger than the odd ones; in addition, the odd-n C$_n$H$_n$ + 1 devices provide well-matched resonance transport channels between the transverse carbon chain and stand-up attached C$_n$H$_n$ + 1 chains, which induces the isolated transmission peak at the Fermi level. So an abnormal even–odd oscillation in conductance in terms of the number of carbon atoms on C$_n$H$_n$ + 1 chains can be found. On the other hand, the striking negative differential resistance behaviors appear in the proposed devices. The mechanisms are analyzed and revealed by the local density of states around the Fermi level at zero bias, with the evolution of the molecular projected self-consistent Hamiltonian associated with the transmission spectrum under different applied bias.