Magnetic-field-induced Stoner transition in a dilute quantum Hall system

In a recent paper [Phys.Rev.B.\textbf{84}, 161307 (2011)], experimental data on spin splitting in the integer quantum Hall effect has been reported in a high mobility dilute 2D electron gas with electron density as low as 0.2 $\times$ 10$^{11}$ cm $^{-2}$. In this work, we show that an excellent \emph{quantitative} description of these data can be obtained within the model of the magnetic-field-induced Stoner transition in the quantum Hall regime. This provides a powerful tool to probe the non-trivial density dependance of electron-electron interactions in the dilute regime of the 2D electron gas.