Quantum interference effects in biphenyl dithiol for gas detection

Abstract

Based on density functional theory and non-equilibrium Green's function method, we investigate the transport properties of four different gases (NO, NO₂, NH₃, and CO) adsorbed on biphenyl dithiol molecules coupled to gold leads. Since the transmission function is strongly affected by quantum interference, namely antiresonance and Fano resonances, significant changes in conductance caused by the adsorption of molecular gases are archived. Our findings suggest that biphenyl dithiol exhibits strong sensitivity for NO and NO₂ which results from their interference features being close to the Fermi energy of the gold leads and dominate the transport of the system. Moreover, the quantum interference effects also result in enhanced and suppressed conductance, which enable us to significantly improve the selectivity. In particular, a distinction between NO, NO₂ and NH₃ gases based on the biphenyl dithiol appears possible.