Localization And Interference Induced Quantum Effects At Low Magnetic Fields In Ingaas/Gaas Structures

The longitudinal rho(xx)(B, T) and Hall rho(xy)(B, T) resistances are experimentally investigated in n-InGaAs/GaAs nanostructures with a single and double quantum wells in the magnetic field range B = 0-2.5 T and temperatures T = 1.8-20 K. It is shown that the origin of the temperature-independent point located at omega(c)tau congruent to 1 on the rho(xx)(B, T) curves is due to the combined action of the classical cyclotron motion and the quantum interference effects of weak localization and electron-electron interaction. The results obtained indicate that the transition from the dielectric phase to the phase of the quantum Hall effect is a crossover from weak localization (quantum interference effects in a weak magnetic field) to strong localization in quantizing magnetic fields in the quantum Hall effect regime.