Time and current dependencies of transport at the v=2/3 phase transition in narrow quantum wells

Abstract

The spin unpolarised to spin polarised v=2/3 phase transition is studied in narrow quantum wells. The phase transition is mapped in the filling factor (ν), density (n)-plane and is well described assuming a Image dependence of the Composite Fermion effective mass. At high currents the huge longitudinal resistance anomaly appears along the phase boundary. A model is presented that treats the current induced nuclear spin polarisation as an additional source of disorder, which drastically alters the initial domain structure present at the phase boundary. Time and current dependent measurements at constant magnetic field indicate that a large alternating Hall field is necessary to maintain the high resistance state.