The on-surface synthesis of nonacene has been accomplished by dehydrogenation of an air-stable partially saturated precursor, which could be aromatized by using a combined scanning tunneling and atomic force microscope as well as by on-surface annealing. This transformation allowed the in-detail analysis of the electronic properties of nonacene molecules physisorbed on Au(111) by scanning tunneling spectroscopy measurements. The spatial mapping of molecular orbitals was corroborated by density functional theory calculations. Furthermore, the thermally induced dehydrogenation uncovered the isomerization of intermediate dihydrononacene species, which allowed for their in-depth structural and electronic characterization.

We study thermoelectric effects in a Kondo correlated quantum dot coupled to ferromagnetic electrodes by calculating conductance, thermopower, and thermal conductance in the Kondo regime. We also study the effect of the asymmetry in the coupling to the leads, which has important consequences for antiparallel magnetization configuration. We discuss the thermoelectric figure of merit, tunnel magnetoresistance, and violation of the Wiedemann-Franz law in this system. The results agree with recently measured thermopower of the quantum dot defined in a two-dimensional electron gas.

A structural model of Au induced Si(553) surface is proposed. The model is based on the recently revised value of Au coverage of 0.48 monolayers, which suggests the formation of two gold chains on each Si(553) terrace. The resulting structural model, such as the models of other vicinal Si surfaces, features the honey-comb chain, but no buckling of the step edge is observed, unlike in the case of the Si(335)-Au and Si(557)-Au surfaces. The present model is more stable than the models with single Au chain only, and agrees well with existing experimental data. In particular, calculated band structure, featuring two metallic bands coming from the hybridization of gold in both chains with neighboring Si atoms, matches well the photoemission data. Moreover, theoretical scanning tunneling microscopy topographs remain in good agreement with the experiment.

We study thermoelectric phenomena in a system consisting of a strongly correlated quantum dot coupled to external leads in the Kondo regime. We calculate linear and nonlinear electrical and thermal conductance and thermopower of the quantum dot and discuss the role of asymmetry in the couplings to external electrodes. In the linear regime electrical and thermal conductances are modified, while thermopower remains unchanged. In the nonlinear regime the Kondo resonance in differential conductance develops at nonzero source-drain voltage, which has important consequences on thermoelectric properties of the system, and the thermopower starts to depend on the asymmetry. We also discuss Wiedemann-Franz relation, thermoelectric figure of merit, and validity of the Mott formula for thermopower.

We study the electron transport through the quantum dot coupled to the normal metal and BCS-like superconductor (N - QD - S) in the presence of the Kondo effect and Andreev scattering. The system is described by the single impurity Anderson model in the limit of strong on-dot interaction. We use recently proposed equation of motion technique for Keldysh nonequilibrium Green's function together with the modified slave boson approach to study the electron transport. We derive formula for the current which contains various tunneling processes and apply it to study the transport through the system. We find that the Andreev conductance is strongly suppressed and there is no zero-bias (Kondo) anomaly in the differential conductance. We discuss effects of the particle-hole asymmetry in the electrodes as well as the asymmetry in the couplings.