Interplay of electron-magnon scattering and spin-orbit induced electronic spin-flip scattering in a two-band Stoner model (2304.14978v3)

Abstract: This paper presents a theoretical investigation of the influence of electron-magnon scattering processes on the ultrafast demagnetization in itinerant ferromagnets. In the framework of a ferromagnetic model system, we compute the spin-dependent dynamics of electrons in itinerant Bloch states including electron-magnon and electron-electron scattering. Our approach includes both electron-magnon and electron-electron scattering processes on an equal footing. While the former process flips the electronic spin accompanied by the creation or destruction of a magnons, the latter exchanges electronic angular momentum with the lattice due to the influence of spin-orbit coupling. We show that the interplay of the two different scattering mechanisms leads to the creation of magnons and a transfer of angular momentum to the lattice that, for a realistic choice of the electron-magnon interaction and excitation conditions, is considerably more efficient than spin-orbit assisted electron-electron scattering alone. This process of magnon creation and spin-lattice coupling constitutes an essentially non-equilibrium microscopic scenario for the ultrafast demagnetization process in itinerant ferromagnets.