1997/10/16 by Karyn Le Hur, K. Le Hur · 1 citation
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.56.14058
published as Phys. Rev. B 56 1997 14058 · 22 pages, TEX and 2 figures (long version); to be published in Phys. Rev. B (December 97)
arxiv created 1997/10/16 · openalex publication_date 1997/12/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigate the one-dimensional Kondo lattice model for ferromagnetic Kondo couplings. The so-called ferromagnetic two-leg spin ladder and the S=1 antiferromagnet occur as one-dimensional Kondo insulators. Both exhibit a spin gap. But, in contrast to the strong-coupling limit, the Haldane state which characterizes the two-leg spin-ladder Kondo insulator cannot fight against very weak exterior perturbations. First, by using standard bosonization techniques, we prove that an antiferromagnetic ground state occurs by doping with few holes; it is characterized by a form factor of the spin-spin correlation functions which exhibits two structures, respectively, at q=\ensuremathπ and q=2kF. Second, we prove precisely by using renormalization-group methods that the Anderson localization inevitably takes place in that weak-coupling Haldane system, by the introduction of quenched randomness; the spin-fixed point rather corresponds to a ``glass'' state. Finally, a weak-coupling analog of the S=1 antiferromagnet Kondo insulator is proposed; we show that the transition into the Anderson-localization state may be avoided in that unusual weak-coupling Haldane system.