Using Molecular States to Probe Spin and Self-Assembly Properties of Single Molecules
- Author(s): Wagner, Peter
- Advisor(s): Ho, Wilson
- et al.
Here, we discuss the enhancement of the scanning tunneling microscope (STM) through the functionalization of the STM tip with single molecules. Using a sub-Kelvin STM, we observe that a magnetic molecule can be reproducibly transferred from the surface to the tip and forms a Kondo state. This many-body resonance undergoes exchange splitting in the proximity of another magnetic molecule adsorbed on the substrate surface and exhibits effects of spin polarization in the mutual inelastic conductance. The Kondo tip influences the inelastic spin-flip excitation in the magnetic molecule and a hybrid Kondo-spin excitation state emerges. These results reveal magnetic sensing between a many-body resonance and discrete excitations between two magnetic molecules.We also study molecule-molecule and molecule-surface interactions as they are fundamental to controlling the bottom-up formation of two-dimensional materials on metal surfaces. Using a carbon monoxide (CO) terminated scanning tunneling microscope (STM) tip, the orientation and adsorption site of 1,3,5-tribromobenzene and 1,3,5-tribromoborazine can be resolved in clusters on metal surfaces. By monitoring the perturbation of the CO inelastic modes at different distances, the nature and magnitude of the forces from the sample system on the CO probe can be explored. We investigate the relationship between the calculated surface adsorption energy, intermolecular binding energy, and clustering behavior of these tri-halogenated benzene and borazine molecules.