Identification of the physical parameters of the paramagnetic phase of the one-dimensional Kondo lattice model done by introducting a nonmagnetic quantum state with rotating order parameters

Abstract

The paramagnetic phase of the one-dimensional Kondo lattice model is investigated for electron densities below half-filling using a new mean-field approach. The physical parameters that govern this phase are identified to be the spin-flip processes of both the localized and itinerant spins. A nonmagnetic quantum state, where the local magnetization is a rotating vector with a nonzero average length, is proposed in order to describe this phase. This state does not break SU(2) symmetry in agreement with Mermin-Wagner theorem. The line boundary between this phase and the ferromagnetic phase is calculated in the coupling-density phase diagram. Also, expressions are calculated for the velocities of the conduction electrons excitations, and heat capacity and entropy versus temperature are analyzed. Good agreement with many of the available numerical data is achieved.