Screening and Friedel oscillations in inhomogeneous systems with correlated fermions

Abstract: The talk presents theoretical and numerical studies on electronic screening and Friedel oscillations (FO) in correlated fermionic systems in the presence of external inhomogeneity. These spatial oscillations in the electronic densities appear in metals at low temperature in the neighborhood of the impurity due to quantum scattering from the impurity. FO in the Fermi liquid phase, Mott insulating phase, and at the Mott metal to insulator transition are studied in one-, two-, and three-dimensional lattice models. The interacting system has been modeled by the Hubbard Hamiltonian which has been further solved numerically using the real-space dynamical mean-field theory (R-DMFT). According to our numerical studies, FO are damped with the interactions, disappear at the Mott transition and completely beyond it. At finite temperature, FO are damped and slowly disappear as we increase the temperature of the system. At half-filling, the period and phase of FO remain unaltered by the interactions. The Friedel sum rule for the interacting system has been investigated. It is further seen that the interactions weaken the screening effects. In the presence of the interaction, a sign of resonance appears in the spectral function at the impurity site. The predictive numerical results hold promising to motivate future experiments in real materials with correlated electrons.