STM induced manipulation of azulene-based molecules and nanostructures: the role of the dipole moment

• Published in: Nanoscale Vol. 12; no. 48; pp. 24471 - 24476
• Main Authors: Kühne, Tim, Au-Yeung, Kwan Ho, Eisenhut, Frank, Aiboudi, Oumaima, Ryndyk, Dmitry A, Cuniberti, Gianaurelio, Lissel, Franziska, Moresco, Francesca
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 23.12.2020
• Subjects: Azulene; Charge distribution; Dimers; Dipole moments; Electric fields; Low temperature; Metallography; Movement; Nanostructure; Scanning tunneling microscopy; Voltage pulses
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d0nr06809h

Among the different mechanisms that can be used to drive a molecule on a surface by the tip of a scanning tunneling microscope at low temperature, we used voltage pulses to move azulene-based single molecules and nanostructures on Au(111). Upon evaporation, the molecules partially cleave and form metallo-organic dimers while single molecules are very scarce, as confirmed by simulations. By applying voltage pulses to the different structures under similar conditions, we observe that only one type of dimer can be controllably driven on the surface, which has the lowest dipole moment of all investigated structures. Experiments under different bias and tip height conditions reveal that the electric field is the main driving force of the directed motion. We discuss the different observed structures and their movement properties with respect to their dipole moment and charge distribution on the surface. The voltage-pulse manipulation of azulene-based single molecules and dimers adsorbed on Au(111) is studied with respect to dipole moment and charge distribution of the structures on the surface.