Spin-flip excitations and Stoner ferromagnetism in a strongly correlated quantum Hall system

Abstract

Spin-flip excitations in a quantum Hall electron system at fixed filling factor $\ensuremath{\nu}=2$ are modeled and studied under conditions of a strong Coulomb interaction when the ``Landau level mixing'' is a dominant factor determining the excitation energy. The ``one-exciton'' approach used for the purely electronic excitations in question allows us to describe the Stoner transition from the unpolarized/paramagnet state to the polarized/ferromagnet one. The theoretical results are compared with the available experimental data.