Engineering Giant Rabi Splitting via Strong Coupling between Localized and Propagating Plasmon Modes on Metal Surface Lattices: Observation of √N Scaling Rule.

We present a strong coupling system realized by coupling the localized surface plasmon mode in individual silver nanogrooves and propagating surface plasmon modes launched by periodic nanogroove arrays with varied periodicities on a continuous silver medium. When the propagating modes are in resonance with the localized mode, we observe a √N scaling of Rabi splitting energy, where N is the number of propagating modes coupled to the localized mode. Here, we confirm a giant Rabi splitting on the order of 450-660 meV (N = 2) in the visible spectral range, and the corresponding coupling strength is 160-235 meV. In some of the strong coupling cases studied by us, the coupling strength is about 10% of the mode energy, reaching the ultrastrong coupling regime.

Aromatic Azide Transformation on the Ag(111) Surface Studied by Scanning Probe Microscopy.

Chemical transformation of 9-azidophenanthrene on the Ag(111) surface was studied by nc-AFM in UHV. High-resolution imaging supported by first-principle calculations revealed the structure of the final products that originated from a common and elusive 9-phenanthryl nitrenoid intermediate chemisorbed on the Ag(111) surface. A formal nitrene insertion into the C-H bond along with its dimerisation and hydrogenation were identified as main reaction channels. Thus, the ability of aryl azides to form covalent σ- and π-bonds between their transformation products on a solid surface was demonstrated at a single-molecule level.

Dynamics of Spatially Confined Bisphenol A Trimers in a Unimolecular Network on Ag(111).

Bisphenol A (BPA) aggregates on Ag(111) shows a polymorphism between two supramolecular motifs leading to formation of distinct networks depending on thermal energy. With rising temperature a dimeric pairing scheme reversibly converts into a trimeric motif, which forms a hexagonal superstructure with complex dynamic characteristics. The trimeric arrangements notably organize spontaneously into a self-assembled one-component array with supramolecular BPA rotors embedded in a two-dimensional stator sublattice. By varying the temperature, the speed of the rotors can be controlled as monitored by direct visualization. A combination of scanning tunneling microscopy and dispersion-corrected density-functional tight-binding (DFTB-vdW(surf)) based molecular modeling reveals the exact atomistic position of each molecule within the assembly as well as the driving force for the formation of the supramolecular rotors.