title: Cyclotron spin-flip excitations in a nu = 1/3 quantum Hall ferromagnet.
abstract: Inelastic light scattering spectroscopy discloses a novel type of cyclotron spin-flip excitation in a quantum Hall system around the nu = 1/3 filling. The excitation energy follows qualitatively the degree of electron spin polarization, reaching a maximum value at nu = 1/3. This characterizes the new excitation as a nu = 1/3 ferromagnet eigenmode. The mode energy exceeds drastically the theoretical prediction obtained within the renowned single-mode approximation. We develop a new theoretical approach where the basis set is extended by adding a double-exciton component representing the cyclotron magnetoplasmon and spin wave coupled together. This double-mode approximation, inferred to be responsible for substantially reducing the gap between theoretical and experimental results, shows that the cyclotron spin-flip excitation is effectively a four-particle state.
authors.affiliation: Institute of Solid State Physics, RAS, Chernogolovka, 142432 Russia.
authors.forename: A B
authors.initials: AB
authors.lastname: Van'kov
authors.forename: L V
authors.initials: LV
authors.lastname: Kulik
authors.forename: S
authors.initials: S
authors.lastname: Dickmann
authors.forename: I V
authors.initials: IV
authors.lastname: Kukushkin
authors.forename: V E
authors.initials: VE
authors.lastname: Kirpichev
authors.forename: W
authors.initials: W
authors.lastname: Dietsche
authors.forename: S
authors.initials: S
authors.lastname: Schmult