Piazza, Vincenzo and Pellegrini, Vittorio and Beltram, Fabio and Wegscheider, Werner and Bichler, Max and Jungwirth, Tomàs and McDonald, Allan H.
Hysteresis and first-order phase transition in the two-dimensional electron gas.
Physica E Low-dimensional Systems and Nanostructures 6 (1-4), pp. 108-111.
We report experimental evidence of the first-order phase transitions in the two-dimensional electron gas formed in a gated wide GaAs/AlGaAs quantum well at even-integer quantum-Hall states. At the filling factor values of ν=2,4 and low temperatures, crossing of Landau levels through the application of the gate bias yields a suppression of the quantum-Hall-state excitation gap and hysteretical behaviour of the diagonal resistivity in up and down sweeps of the magnetic field. Detailed many-body calculations indicate the occurrence of a first-order phase transition and allow the determination of the exact properties of the electron ground states involved in the transition.