Searching the Hearts of Graphene-like Molecules for Simplicity, Sensitivity, and Logic

If quantum interference patterns
in the hearts of polycyclic aromatic
hydrocarbons could be isolated and manipulated, then a significant
step toward realizing the potential of single-molecule electronics
would be achieved. Here we demonstrate experimentally and theoretically
that a simple, parameter-free, analytic theory of interference patterns
evaluated at the mid-point of the HOMO–LUMO gap (referred to
as M-functions) correctly predicts conductance ratios of molecules
with pyrene, naphthalene, anthracene, anthanthrene, or azulene hearts.
M-functions provide new design strategies for identifying molecules
with phase-coherent logic functions and enhancing the sensitivity
of molecular-scale interferometers.