g factor of composite fermions around ν=2 from angular-dependent activation-energy measurements

Abstract

We have determined the g factor of composite fermions (CF's) around Landau-level filling factor \ensuremath{\nu}= through angular-dependent thermal-activation energy measurements at several fractional quantum Hall states. The g factors agree to within 10% with the results of earlier coincidence measurements, supporting the concept of a CF with a spin. Deviations from a simple level-crossing scheme cannot be accounted for solely by a broadening of the CF levels.