Magnetic excitations in the periodic Anderson model

Abstract

A study of spin waves in the magnetic phases of the periodic Anderson modelfor a cubic lattice is carried out in the random-phase approximation. Within mean field theory, we determine the ferromagnetic region of the phase diagram at T ¼ 0: The spin wave spectrum is computed along high symmetry directions of the Brillouin zone. An analytical expression for the spin wave dispersion valid in the small momentum limit is derived, and from it the spin wave stiffness is computed. The lowest energy boundaries of the Stoner continuum and of the spin wave dispersive continuum (delta function contributions) are both computed.