arXiv:cond-mat/0105574 · Physical review. B, Condensed matter
Electronic states, Mott localization, electron-lattice coupling, and dimerization for correlated one-dimensional systems
Adam Rycerz, Józef Spałek
Abstract
We discuss the physical properties of strongly correlated electron states for a linear chain obtained with the help of a recently proposed method combining an exact diagonalization in Fock space with an ab initio readjustment of single-particle orbitals in the correlated state. The method extends the current discussion of correlated states, since the properties are obtained with varying lattice spacings. The finite system of N atoms evolves with the increasing interatomic distance from a Fermi-liquid-like state into the Mott insulator. The criteria of the localization are discussed in detail, since the results are already convergent for $N>~8.$ During this process the Fermi-Dirac distribution is smeared out, the effective band mass increases by \ensuremath{\sim}50%, and the spin-spin correlation functions reduce to those for a Heisenberg antiferromagnet. Values of microscopic parameters such as the hopping and the kinetic-exchange integrals, as well as the magnitude of both intraatomic and interatomic Coulomb and exchange interactions are calculated. We also determine the values of various local electron-lattice couplings, and show that they are comparable to the kinetic exchange contribution in the strong-correlation limit. The magnitudes of the dimerization and the zero-point motion are also discussed. Our results provide a canonical example of a tractable strongly correlated system with a precise, first-principles description as a function of interatomic distance of a model system involving all hopping integrals, all pair-site interactions, and exact one-band Wannier functions.