Local Moments Coupled to a Strongly Correlated Electron Chain

Samuel Moukouri; Liang Chen; Laurent G. Caron

doi:10.1103/PhysRevB.53.R488

paper

Local Moments Coupled to a Strongly Correlated Electron Chain

arXiv:cond-mat/9511069 · doi:10.1103/PhysRevB.53.R488

Abstract

A 1D model hamiltonian that is motivated by the recent discovery of the heavy-fermion behavior in the cuprates of the $N d_{2} C u O_{4}$ type is studied. It consists of $t - J$ interacting conduction electrons coupled to a lattice of localized spins through a Kondo exchange term $J_{K}$ . Exact diagonalization and density matrix renormalization group methods are used. The latter method is generalized to arbitrary densities. At half-filling, a spin gap opens for all $J_{K} > 0$ . Away from half-filling $,$ it is shown that, at strong $J_{K}$ % , the ground state is an unsaturated ferromagnet . At weak $J_{K}$ the system is in a paramagnetic phase with enhanced RKKY correlations. The importance of self-screening of the local moments in the depletion regime is discussed. We argue that these findings transcend the specifics of the model.

10 pages, Latex, 4 figures included, to be published in PRB (Rapid Communications)