Cyclotron resonance in the paramagnetic and ferromagnetic phase of a two-dimensional electron gas with even-integer filling factors

Abstract

In a two-dimensional electron gas, the cyclotron frequency depends on ${B}_{\ensuremath{\perp}}$, the component of magnetic field normal to the layer, while the spin splitting depends on the magnitude of B. When an integral number of Landau levels are filled, the system can undergo a paramagnetic-to-ferromagnetic transition. Cyclotron resonance, in the presence of a random impurity potential, displays effects associated with electron-electron interactions and can be used to probe the transition. In this work, cyclotron-resonance line shapes are studied as a function of frequency for both the paramagnetic and ferromagnetic phases.