Composite-Fermion Picture for the Spin-Wave Excitation in the Fractional Quantum Hall System.

Spin-wave excitation mode from the spin-polarized ground state in the fractional quantum Hall liquid with odd fractions (ν = 1/3, 1/5) numerically obtained by the exact diagonalization of finite systems is shown to be accurately described, for wavelengths exceeding the magnetic length, in terms of the composite-fermion mean-field approximation for the spin-wave (magnon) theory formulated in the spherical geometry. This indicates that the composite picture extends to excited states, and also provides the spin stiffness in terms of peculiar exchange interactions.