Cyclotron spin-flip excitations in a nu = 1/3 quantum Hall ferromagnet.
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.
Van'kov
A B
AB
Institute of Solid State Physics, RAS, Chernogolovka, 142432 Russia.
Kulik
L V
LV
Dickmann
S
S
Kukushkin
I V
IV
Kirpichev
V E
VE
Dietsche
W
W
Schmult
S
S