Driving Interference control by side carbon chain in molecular and two dimensional nano-constrictions
Quantum interference effect offers unique route to control the charge transport through nanoscale constrictions. Recently, carbon atomic chain, the sp hybridized carbon allotrope, stimulates the interests to construct ultimate nano-device. Instead of using carbon atomic chain as electron transmitting channel interconnecting nano-components, we explore the possibility of using side carbon chains to change the phase of the transmitting electron and influence the interference pattern of the nano-device. The interference pattern modulation is a general phenomenon, which is demonstrated in a benzene molecular device, a zigzag graphene nanoribbon device and a SiC nanoribbon device. The odd-even oscillation dependence of conductance on the length of side carbon chain is found. Two criteria, i.e. large magnitude of local state in side carbon chain and proper length of side carbon chain, must be satisfied simultaneously to achieve effective interference modulation. By carefully choosing the position and length of side carbon chains, the transmission zero can be moved to Fermi energy. Moreover, the transmission zero induced by destructive interference at Fermi energy can be very robust against strain. This work provides a new possibility to construct nano-device by carbon atomic chains.