Quantum Corrections to Conductivity: From Weak to Strong Localization

Abstract

The results of detailed investigations of the conductivity and Hall effect in gated single-quantum-well GaAs/InGaAs/GaAs heterostructures with two-dimensional electron gas are presented. A successive analysis of the data has shown that the conductivity is diffusive for kFl = 25-2. The absolute value of the quantum corrections for kFl = 2 at low temperature is not small; e.g., it is about 70% of the Drude conductivity at T = 0.46 K. For kFl = 2-0.5 the conductivity looks like the diffusive one. The temperature and magnetic field dependences are qualitatively described within the framework of the self-consistent theory of Vollhardt and Wölfle. The interference correction is therewith close in magnitude to the Drude conductivity so that the conductivity σ becomes significantly less than e2/h. We conclude that the temperature and magnetic field dependences of the conductivity in the whole kFl range are due to changes of the quantum corrections.