Incommensurate spin-density-wave and metal-insulator transition in the one-dimensional periodic Anderson model

We have used the density-matrix renormalization group method to study the ground-state properties of the symmetric periodic Anderson model in one dimension. We have considered lattices with up to Ns=50 sites, and electron densities ranging from quarter to half filling. Through the calculation of energies, correlation functions, and their structure factors, together with careful extrapolations (toward Ns→ ), we were able to map out a phase diagram Uvsn, where U is the electronic repulsion on f orbitals, and n is the electronic density, for a fixed value of the hybridization. At quarter filling, n=1, our data is consistent with a transition at U c1 2, between a paramagnetic (PM) metal and a spin-density-wave (SDW) insulator; overall, the region U 2 corresponds to a PM metal for all n<2. For 1<n 1.5 a ferromagnetic phase is present within a range of U, while for 1.5 n<2, we find an incommensurate SDW phase; above a certain Uc(n), the system displays a Ruderman-Kittel-Kasuya-Yosida behavior, in which the magnetic wave vector is determined by the occupation of the conduction band. At half filling, the system is an insulating spin liquid, but with a crossover between weak and strong magnetic correlations. © 2011 American Physical Society.