Magnetoresistance of composite fermions a

We have studied the temperature dependence of both diagonal and Hall resistivity in the vicinity of (Formula presented) Magnetoresistance was found to be positive and almost independent of temperature: the temperature enters the resistivity as a logarithmic correction. At the same time, no measurable corrections to the Hall resistivity have been found. Neither of these results can be explained within a theory of noninteracting composite fermions or by an analogy with conventional low-field interaction theory. There is an indication that interactions of composite fermions with fluctuations of the gauge field may reconcile the theory and experiment.