Density Matrix Renormalization Group Study of the One-Dimensional Anderson Lattice

Masahiko Okumura, S. Yamada, Masahiko Machida

M. Guerrero, Clare C. Yu

Robert Peters

Fuyuki Matsuda, Masaki Tezuka, Norio Kawakami

We consider the one-dimensional (1D) quasiperiodic Anderson-lattice model, which has quasiperiodically ordered impurities. The sites with an f-orbital are ordered as a “Fibonacci word”, one way to form 1D quasiperiodic orderings. To treat the correlation effect precisely, we use the density matrix renormalization group (DMRG) method. We show that the spin correlation function in the quasiperiodic system gives a characteristic pattern. Also, by analyzing the f-electron number and its fluctuation, we find that a valence transition, which usually occurs in the periodic Anderson model when the on-site interorbital interaction is large, is not sharp in the quasiperiodic system. Finally, we discuss the properties of the quasiperiodic Anderson-lattice model, comparing them against the Anderson-lattice model with randomly located f-orbitals. We find that the quasiperiodic Anderson-lattice model has a similar property to the periodic Anderson model for spin correlation, but also has a similar property to the Anderson-lattice model with randomly located f-orbitals for the valence fluctuation.

Mingru Yang, Steven White

M. Guerrero, Hervé M. Carruzzo

We study the effect of a small dispersion in the f band on the elementary excitations of the one-dimensional Anderson lattice at half filling. We use the density-matrix renormalization-group technique to study the strong-coupling case (large Coulomb repulsion U) and an analytic renormalization-group calculation for weak coupling. When U=0, even a small dispersion in the f band can close the hybridization gap. In contrast, when U is large, the quasiparticle gap remains open and is almost independent of the dispersion in the f band. This means that for a given value of the dispersion, there is a metal-insulator transition for some value of the Coulomb repulsion U. The analytic calculation shows that the transition occurs at U=0. In contrast to the quasiparticle gap, the spin gap is strongly suppressed by the dispersion in the f band. This suppression is associated with the enhancement of antiferromagnetic correlations. \textcopyright{} 1996 The American Physical Society.