Magnetic ordering and non-Fermi-liquid behavior in the multichannel Kondo-lattice model

Abstract

Abstract. Scaling equations for the Kondo lattice in the paramagnetic and magnetically ordered phases are derived to next-leading order with account of spin dynamics. The results are applied to describe various mechanisms of the non-Fermi-liquid (NFL) behavior in the multichannel Kondo-lattice model where a fixed point occurs in the weak-coupling region. The corresponding temperature dependences of electronic and magnetic properties are discussed. The model describes naturally formation of a magnetic state with soft boson mode and small moment value. An important role of Van Hove singularities in the magnon spectral function is demonstrated. The results are rather sensitive to the type of magnetic ordering and space dimensionality, the conditions for NFL behavior being more favorable in the antiferromagnetic and 2D cases. PACS

Scaling theory of magnetism in frustrated Kondo lattices

“…At small |g − g c1 |, the linear behavior of 1/ ln( S(ξ)) takes place in a finite, but wide interval of ξ. This dependence can be observed as a NFL behavior in thermodynamic and transport properties (|C| → T , see [4,25,31]), in particular, in unusual temperature dependences of magnetic susceptibility χ(T) in heavy-fermion systems [32].…”

“…However, if g is somewhat larger, frustrations start to work at ξ ξ 1 , provided that tφ(|J (g ef (ξ))/J|)g 3 ef (ξ 1 )/|2Jρ| = Ag 3 ef (ξ 1 )/ S(ξ 1 ) ∼ 1. (34) We rewrite equation (31) as…”

“…The Kondo renormalization of spin fluctuation frequency in the paramagnetic phase is determined from the second moment of the spin Green's function and in antiferromagnetic phase by calculating the magnon anharmonicity terms [4,24,31]. Generally speaking, q 2 and q 4 terms in the magnon spectrum are renormalized in a different way (the situation is similar to the consideration of the anisotropic Kondo model with renormalized gap [24]), the corresponding prefactors being determined by some averages over the Fermi surface, which are unknown.…”

Degenerate orbital effect in a three-orbital periodic Anderson model

“…Apart from the degenerate orbital effect, the model is also connected with the multichannel Kondo problem. Various mechanisms of non-Fermiliquid behavior were discussed based on a multichannel Kondo lattice model 19 . Compared with the Kondo lattice model, the PAM includes charge degree of freedom, so the physics in it would be more rich.…”