Current induced light emission and light induced current in molecular tunneling junctions

The interaction of metal-molecule-metal junctions with light is considered within a simple generic model. We show, for the first time, that light induced current in unbiased junctions can take place when the bridging molecule is characterized by a strong charge-transfer transition. The same model shows current induced light emission under potential bias that exceeds the molecular excitation energy. Results based on realistic estimates of molecular-lead coupling and molecule-radiation field interaction suggest that both effects should be observable.Comment: 5 pages, 3 figures, RevTeX

Flux switching in magnetic circuits

Flux switching in magnetic circuit

Observation and analysis of Fano-like lineshapes in the Raman spectra of molecules adsorbed at metal interfaces

Surface enhanced Raman spectra from molecules (bipyridyl ethylene) adsorbed on gold dumbells are observed to become increasingly asymmetric (Fano-like) at higher incident light intensity. The electronic temperature (inferred from the anti-Stokes (AS) electronic Raman signal increases at the same time while no vibrational AS scattering is seen. These observations are analyzed by assuming that the molecule-metal coupling contains an intensity dependent contribution (resulting from light-induced charge transfer transitions as well as renormalization of the molecule metal tunneling barrier). We find that interference between vibrational and electronic inelastic scattering routes is possible in the presence of strong enough electron-vibrational coupling and can in principle lead to the observed Fano-like feature in the Raman scattering profile. However the best fit to the observed results, including the dependence on incident light intensity and the associated thermal response is obtained from a model that disregards this coupling and accounts for the structure of the continuous electronic component of the Raman scattering signal. The temperatures inferred from the Raman signal are argued to be only of qualitative value.Comment: 20 pages, 12 figure

Kubo-Anderson theory of polariton lineshape

We apply the Kubo-Anderson stochastic theory of molecular spectral lineshape to the case of polaritons formed in the collective strong coupling regime. We investigate both the fast and slow limits of the random frequency modulation of the emitter as well as the intermediate regime and show how the interplay between the characteristic timescales of the cavity and the molecular disorder is expressed in the observed polaritons lineshapes. The analytical solution obtained for the slow limit is valid for any ratio between the inhomogeneous broadening of the molecules and the Rabi splitting, especially relevant for molecular polaritons where these two quantities can be of the same order of magnitude