Spotlights on Recent JACS Publications

摘要

Quantum interference is one of the most intriguing phenomena in quantum physics. Single photons or electrons pass through a double slit and the matter waves interfere, either constructively or destructively, depending on the phases of the matter waves. Recently, this phenomenon has been observed with electrons sent through single molecules, whereby differences in the conductance are attributed, at least in part, to quantum interference. However, because conductance measurements are performed on molecules with different chemical structures, it is impossible to measure the conductance resulting from quantum interference alone. Now, Marius Bürkle, Nongjian Tao, Yoshihiro Asai, and coworkers report a way to pin down quantum interference of electrons passing through two identical isomers of tetraphe-nylbenzene (DOI: 10.1021/jacs.6bl0837). The molecule consists of four benzene rings attached to a central benzene moiety that functions like a roundabout for electrons. In one configuration of the injection point, the electrons undergo constructive interference. With a different injection point, the conductance becomes 1 order of magnitude lower because of destructive interference. Ab initio calculations for the conductance show close concordance with the experimental results. The work presents a new approach to quantify quantum interference effects in molecular conductors.