Interaction ruled temperature dependence of the electron cyclotron mass in GaAs heterojunctions

Cyclotron resonance of inversion layer electrons in GaAs was studied from liquid helium temperatures up to 110 K for densities smaller than 10(exp11)cm(-2) . A continuous red shift of the resonance position was observed with increasing temperature. A quantitative analysis of the experiment demonstrates that electron-electron interactions which introduce a coupling of the electrical dipole transitions between the Landau levels are responsible for this shift.