2008/06/30 by Myron D. Kapetanakis, M. D. Kapetanakis, I. E. Perakis
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Electronic and Structural Properties of Oxides #Magnetic and transport properties of perovskites and related materials #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.78.155110
published as Physical Review B 78, 155110 (2008) · 13 pages, 10 figures, published in Phys. Rev. B
openalex publication_date 2008/10/10 · arxiv created 2008/10/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study spin relaxation and dynamics of collective spin excitations in correlated double-exchange ferromagnets. For this, we introduce an expansion of the Green's functions equations of motion that treats nonperturbatively all correlations between a given number of spin and charge excitations and becomes exact within a subspace of states. Our method treats relaxation beyond Fermi's golden rule while recovering previous variational results for the spin-wave dispersion. We find that the momentum dependence of the spin-wave dephasing rate changes qualitatively due to the on-site Coulomb interaction, in a way that resembles experiment, and depends on its interplay with the magnetic exchange interaction and itinerant spin lifetime. We show that the collective spin relaxation and its dependence on the carrier concentration depend sensitively on three-body correlations between a spin excitation and a Fermi sea electron and hole. The above spin dynamics can be controlled via the itinerant carrier population.