Spin-wave dispersion in ferromagnetic semiconductor superlattices and thin films in the narrow-band limit

Theory of Carrier-Mediated Magnonic Superlattices

“…These structures were studied mainly in the context of spin-carrier transport for applications in the field of spintronics [6] as giant magnetoresistance (GMR) by manipulating the (anti)ferromagnetic coupling between Mn layers [7][8][9][10]. To our knowledge, spin waves in magnetic semiconductor superlattices were only studied in the narrow-band limit under the action of direct impurity exchange, where carriers motion plays no role [11]. This family of hybrid materials present a natural advantage, acting as interfaces between (spin)electronic and magnonic degrees of freedom.…”

“…Several features stand out in Eq. (11). The most important one is the presence of negative-energy excitations (Ω < 0).…”