PUMA
Istituto dei materiali per l'elettronica ed il magnetismo     
Acquarone M., Ventura C. I. Renormalized spin waves in the AF Heisenberg-Kondo model for heavy fermions. In: SATT14 - 14esima Conferenza Superconduttori ad Alta Temperatura di Transizione (Istituto IMEM Parma, 19-21 Marzo 2008).
 
 
Abstract
(English)
Recent neutron measurements in CeIn_3 and CePd_2Si_3 evidenced spin wave excitations at low temperatures. These heavy fermion compounds exhibit AF long range order, but a strong competition between the RKKY interaction and Kondo effect is evidenced by their nearly equal Néel and Kondo temperatures. Our aim is to show how magnons in the AF phase of these compounds can be dexribed by a microscopic Heisenberg-Kondo model [J. Iglesias et al. PRB 56, 11820 (1997)] introduced before for the non-magnetic phase. The model includes the correlated Ce 4f electrons hybridized with the conduction band, and we consider competing RKKY and Kondo AF couplings. Carrying on a series of unitary transformations we perturbatively derive an effective Hamiltonian which, projected onto the AF electron ground state, describes the spin wave excitations, renormalized by their interaction with the correlated itinerant electrons. We numerically study how the different parameters of the model influence the renormalization of the magnons and compare our results with available experimental data, finding good agreement with the spin wave measurements in cubic CeIn_3
Subject 71.10-w
71.20Eh


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