Negative magnetoresistance effects in metallic n-type GaSb

摘要

A negative magnetoresistance at low magnetic fields and low temperatures was evidenced in n-type GaSb samples having an electron density just above the critical value for the metal-insulator transition and was interpreted in terms of quantum-interference effects. The inelastic scattering time was derived as a function of the temperature by the analysis of the data with a standard model, which includes weak localization and electron-electron interaction effects. The results of the fitting and the Isawa electron-electron scattering time were found to agree only if a nonnegligible amount of disorder is taken into account in the quantum-interference correction to the conductivity near the metal-insulator transition. These results are discussed in the light of the structural characterization of the investigated samples. The negative magnetoresistance effects were also observed in non-Ohmic measurements, with a behavior consistent with the usual electron temperature model.