Odd-Even Effects of Electronic Transport in Carbon-Chain-Based Molecular Devices

Electronic transport properties of two Au electrodes are examined on the basis of carbon chains with different numbers of carbon atoms, capped with two end groups NO2 and NH2, connected to their surfaces. The first-principles analysis of the microscopic nature reveals that their I-V characteristics and rectifying behaviors show obvious odd-even effects, namely, different bond patterns for even- and odd-numbered carbon atoms can obviously affect the rectifying ratio and directions, charge transfer, electronic transmission possibility, and evolutions of molecular orbitals.