The Role of Quantum Interference in Determining Transport Properties of Organic Molecules

An analytic approach to the electron transport phenomena in molecular devices is presented. Analyzed devices are composed of organic molecules attached to the two semi-infinite electrodes. Molecular system is described within the tight-binding model, while the coupling to the electrodes is analyzed through the use of Newns-Anderson chemisorption theory. The current-voltage (I-V) characteristics are calculated through the integration of transmission function in the standard Landauer formulation. The essential question of quantum interference effect of electron waves is discussed in three aspects: (i) the geometry of molecular bridge and (ii) the presence of an external magnetic field and (iii) the strength of the molecule-to-electrodes coupling.