Hole doping and disorder effects on the one-dimensional Kondo lattice, for ferromagnetic Kondo couplings

Article

关键词: 2 DIMENSIONS;    FIELD-THEORY;    SPIN CHAINS;    SUPERCONDUCTIVITY;    MODEL;    BOSONIZATION;    LADDERS;    STATE;    GAP;   

DOI  :  10.1103/PhysRevB.56.14058

来源: SCIE

【 摘 要 】

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=pi and q=2k(F). 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 maybe avoided in that unusual weak-coupling Haldane system.

【 授权许可】

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