Properties of a correlated nanoscopic chain close to the metal-insulator transition

We review our recent results concerning the electronic properties of a nanoscopic system with inclusion of long‐range Coulomb interactions that are obtained by combining exact diagonalization in the Fock space with an ab initio method (EDABI). The system evolution is discussed as a function of lattice parameter R. A transformation from a nanometal to localized spin system is observed. With the help of a finite‐size scaling we determine the discontinuity of the momentum distribution at the Fermi points. Our results imply Fermi‐liquid‐like behavior for R ≲ 3a$_{0}$ (a$_{0}$ is the Bohr radius). The quasiparticle mass is almost divergent at the localization threshold, where the particle distribution of the Fermi‐Dirac type gets smeared out. The charge‐gap evolution is compared with that of the Slater gap. Also, the single‐particle spectral function and the corresponding density of states are presented. The analysis is performed using 1s‐like Gaussian‐type STO‐3G basis.