Phase transition and chirality switching of dibenzopentacene on Pb(111) surface driven by Coulomb expansion.

The dibenzopentacene (DBPen) molecules on the Pb(111) substrate have been investigated using low-temperature scanning tunneling microscopy. Under the influence of an electric field, DBPen molecules undergo the phase transitions between the 2D mobile phase and the close-packed phase, as well as point and organizational chirality switching. First-principles calculations demonstrate that the electric field significantly modulates the charge transfer from the substrate to the molecules and induces the Coulomb expansion of the molecular lattice, resulting in phase transitions and chirality switching. Our results contribute to understanding the phase control and chirality manipulation of self-assembled molecular structures on solid surfaces.