Abstract
A diagrammatic expansion is developed for the partition function of a lattice of spin-$j$ local moments interacting with a band via the Coqblin-Schrieffer exchange interaction. By examining the limit of large spin degeneracy, $N=2j+1$, a $\frac{1}{N}$ expansion is obtained for the partition function, which clearly exhibits how local spin fluctuations are enhanced by large spin degeneracy. The competition between the Ruderman-Kittel-Kasuya-Yosida interaction and local Kondo spin fluctuations is examined using scaling theory, and the critical value of the Kondo coupling constant above which a spin-compensated Kondo-lattice ground state is stable is shown to tend to zero as $O(\frac{1}{N})$, providing new justification for the applicability of the Kondo-lattice model to rare-earth systems. Physical arguments are advanced, based on the nature of the crossover to the strong-coupling regime, which suggest that the low-temperature excitations of the Kondo lattice form a narrow band of heavy fermions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
