Light scattering by low lying quasiparticle excitations in the fractional quantum Hall regime

Low lying excitations of electron liquids in the fractional quantum Hall (FQH) regime are studied by resonant inelastic light scattering methods. We present here results from charge and spin excitations of FQH states in the lowest spin-split Landau levels that are of current interest. In the range of filling factors View the MathML source, we find evidence that low-energy quasiparticle excitations can be interpreted with spin-split composite fermion quasi-Landau levels. At FQH states around View the MathML source, we find well-defined excitations at View the MathML source and View the MathML source that are consistent with a spin-unpolarized population of quasi-Landau levels.