Temperature Dependent Scattering of Composite Fermions

We have studied the temperature dependent resistivity at exactly half Landau level filling of a high-quality two-dimensional electron system in high magnetic field. The experimental data can be well described in terms of a standard degenerate system of fermions at zero magnetic field being scattered by impurities and acoustic phonons. The gauge-field-mediated phonon scattering contributes a ${T}^{\ensuremath{-}3}$ dependence to the composite fermion mobility. The effective mass of composite fermions is obtained from the temperature dependence of composite fermion-impurity scattering.