▎ 摘　　要

Using the nonequilibrium Green function formalism combined with density functional theory, we studied the electronic transport properties of nanohole defective zigzag graphene nanoribbon (ZGNR) junctions. A side alkene chain is connected to the edge of the defective ZGNR in the scattering region. We find that the transport properties of the defective ZGNR junction are strongly dependent on the parity of the number of carbon atoms in the side alkene chain. The side chain can switch on (even) and off (odd) the transport channel of our proposed junction. It is found that the transmissions for the side chains with an even number of carbon atoms are around 2G(0), but they are around 1G(0) for the side chains with an odd number of carbon atoms. The origin of this peculiar behavior is analyzed as due to the electronic states at the edge of the defective ZGNR which are modulated by the side-chain length. Our theoretical study shows that it is feasible to control the conduction of ZGNR by changing the side-chain length via external modulations such as chemical methods, which may stimulate experimental investigations in the future.