Driving and controlling nanoscale electron correlations

The proposed research project concerns the theoretical description of strongly correlated electron systems confined in low dimensions ranging from quantum dots and quantum wires to organic molecules and clusters of transition metal oxides. The general aim of the project is two-fold: (i) the understanding of correlation effects stemming from the Coulomb interaction in low dimensions; (ii) the search for new routes to manipulate the electronic, magnetic, and transport properties of correlated materials, relevant for technological application. Both aspects stand at the forefront of research in modern theoretical condensed matter physics. In order to achieve this challenging goals the project merges aspects of method development with physical applications. Despite the wide range of physical systems considered, from the methodological point of view the proposed research project takes advantage of a unified many-body formalism, which is able to provide a quantitative description of the electronic structure of both low-dimensional and inhomogeneous systems. In this respect, the dynamical mean-field theory (DMFT) and its extensions allow for a completely non-perturbative treatment of electronic correlations. The underlying diagrammatic many-body formalism allows to compute dynamical correlation functions, which are directly related to experimentally accessible physical quantities. Moreover, the knowledge of two-particle vertex functions also represents a fundamental building block in order to include non-local spatial correlations beyond mean-field, within the dynamical vertex approximation, as it was recently shown by the principal investigator and coworkers in the context of correlated nanostructures. The development of a suitable analytic continuation procedure will grant the access to charge and spin transmission function for a direct comparison with experiments. Finally, within the present project the method will also be extended to the Keldysh contour in order to explore the quantum dynamics and the relaxation toward the steady-state of correlated quantum systems far from equilibrium, as well as the electronic structure and the transport properties of correlated nanostructures in the presence of bias voltage and driving external fields. The flexibility of the proposed approach will allow to investigate the role of electronic correlation in a wide range of physical systems of interest. The applications include the study of both charge and spin correlations in strongly correlated nanostructures. In particular, the principal investigator will explore: (i) the entanglement properties of spatially-separated Cooper pairs in systems of coupled quantum dots in the presence of a superconducting environment; (ii) the possibility of tuning the edge magnetism and the magnetic correlations in graphene nanoflakes by means of carrier doping; (iii) the possibility to manipulate transport properties of fullerenes through static and dynamical distortions.

No additional funding sources recorded.