The spin excitation spectrum in quantum Hall systems: Insights from light scattering experiments
10 April 2007
Collective spin excitations in quantum Hall systems axe studied via inelastic light scattering. In the fractional quantum Hall effect regime, composite fermion spin excitations axe observed in the range 1/3 v 2/5. They reveal a transition from free to strongly interacting composite fermions. At v=1, a shift of the spin-wave energy at finite wavevector from the bare Zeeman energy is observed. It allows us to evaluate the spin-stiffness of the quantum Hall ferromagnet.