Spin-density wave in a Kondo lattice

An Anderson model with N-fold degeneracy in the Kondo regime is considered. It is presumed that the electron-electron correlations in the system of f electrons have their maximum strength. A criterion for instability against the formation of a weakly antiferromagnetic phase superposed on the Kondo state is obtained by the auxiliary-boson method using the 1/N expansion. An effective interaction leading to the formation of magnetic ordering appears because of the spin fluctuations in the system of localized electrons. The phase diagram of the system is constructed. Zh. éksp. Teor. Fiz. 111, 600–614 (February 1997)