Strong signature of electron-vibration coupling in molecules on Ag(111) triggered by tip-gated discharging
Chao Li, Christoph Kaspar, Ping Zhou, Jung‐Ching Liu, Outhmane Chahib, Thilo Glatzel, Robert Häner, Ulrich Aschauer, Silvio Decurtins, Shi‐Xia Liu, Michael Thoss, Ernst Meyer, Rémy Pawlak
Abstract
Abstract Electron-vibration coupling is of critical importance for the development of molecular electronics, spintronics, and quantum technologies, as it affects transport properties and spin dynamics. The control over charge-state transitions and subsequent molecular vibrations using scanning tunneling microscopy typically requires the use of a decoupling layer. Here we show the vibronic excitations of tetrabromotetraazapyrene (TBTAP) molecules directly adsorbed on Ag(111) into an orientational glassy phase. The electron-deficient TBTAP is singly-occupied by an electron donated from the substrate, resulting in a spin 1/2 state, which is confirmed by a Kondo resonance. The TBTAP •− discharge is controlled by tip-gating and leads to a series of peaks in scanning tunneling spectroscopy. These occurrences are explained by combining a double-barrier tunneling junction with a Franck-Condon model including molecular vibrational modes. This work demonstrates that suitable precursor design enables gate-dependent vibrational excitations of molecules on a metal, thereby providing a method to investigate electron-vibration coupling in molecular assemblies without a decoupling layer.