Coqblin-Schrieffer impurity in a singular metal

Article

关键词: GAPLESS FERMI SYSTEMS;    CONFORMAL-FIELD-THEORY;    KONDO PROBLEM;    MAGNETIC-IMPURITIES;    LUTTINGER LIQUID;    RENORMALIZATION-GROUP;    FINITE TEMPERATURE;    HEISENBERG-MODEL;    BEHAVIOR;    ANDERSON;   

DOI  :  10.1103/PhysRevB.62.6877

来源: SCIE

【 摘 要 】

A Coqblin-Schrieffer impurity of spin S coupled to the boundary of an open SU(N)-invariant t-J chain with N= 2S+ 2 is studied. The model is integrable as a function of one coupling parameter v for arbitrary spin and band filling. The system is coupled to a reservoir of electrons and as a function of the chemical potential the host chain has a critical point corresponding to the van I-love singularity of the empty band of charges. In the neighborhood of this critical point we study the low-temperature properties of the impurity as a function of v. For constant chemical potential we obtain two critical coupling values v(1)= - 1/2 and v(2)=0, Separating phases in which the impurity spin is completely compensated (Kondo effect), partially screened (undercompensated impurity), or decoupled from the chain (free spin). The partial compensation occurs as a consequence of a thermally activated Kondo effect in the region v(1) < v < v(2). The possible realization of such a finite temperature Kondo effect in narrow-gap semiconductors is discussed.

【 授权许可】

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