Electron-spin resonance in a quantum dot

We discuss electron-spin resonance in a single quantum dot at filling factor ν≲2. The exchange interaction leads to an enhanced effective $g_{\mathrm{eff}}^{*}$ factor, which in turn gives rise to spatially separated regions of compressible and incompressible states with different spin orientations in the dot. These can be treated as electrostatically coupled dot systems within the original dot. Transport measurements under microwave radiation provide an experimental tool to induce spin transitions between these dots. Measurements indicating a spin-flip transition are presented.