The role of confinement and interaction in the emergence of aromatic features in nanoscale synthetic molecules*

It has recently been demonstrated that the electronic structure of polyaromatic hydrocarbons can be qualitatively reproduced by quantum corrals made via atomic manipulation. This presents a quandary since the electronic structure of these molecules has been ascribed to a resonating valence bond like state requiring strong confinement to molecular orbitals and significant electron-electron interactions. However, quantum corrals fundamentally exhibit single-electron physics as evidenced by a short lifetime for an electron in a corral, resulting in the absence of Coulomb effects between electrons. We examine this problem from the experimental data obtained via scanning tunneling spectroscopy and topography, tight-binding modeling of hopping and interaction Hamiltonians, as well as density functional theory calculations to determine what aspects of the fully-interacting picture can be produced by the single-electron approach.