Quantum Interference in Coherent Molecular Conductance

JULIAN RINCON, K. HALLBERG, A. A. ALIGIA AND S. RAMASESHA

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2009 vol. 103 p. 2668071 - 2668074

0031-9007

   Coherent electronic transport through individual molecules is crucially sensitive to quantum interference. We investigate the zero-bias and zero-temperature conductance through pi-conjugated annulene molecules weakly coupled to two leads for different source-drain configurations, finding an importantreduction for certain transmission channels and for particular geometries as a consequence of destructive quantum interference between states with definite momenta. When translational symmetry is broken by an external perturbation we find an abrupt increase of the conductance through those channels. Previous studies concentrated on the effect at the Fermi energy, where this effect is very small. By analyzing the effect of symmetry breaking on the main transmission channels we find a much larger response thusleading to the possibility of a larger switching of the conductance through single molecules.