Two-component cyclotron resonance in quantum Hall systems

Effects of electron-electron interactions on spin-split and mass-split cyclotron resonance (CR) in a quantum Hall regime are studied by means of numerical diagonalization in finite-size systems. In the case of spin-split CR, the spectra at low temperatures show a simple mode-repulsion behavior at low filling factors, while they show more complicated behaviors at high filling factors including motional narrowing when the electron density for up-spin and that for down-spin are comparable. The spectra at high temperatures can be understood in terms of increase in the effective filling factor. The results qualitatively explain experiments in ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ heterostructures. In the case of mass-split CR, the spectra show only a mode-repulsion behavior independent of temperatures and filling factors.