Electron-electron interaction in doped GaAs at high magnetic field

We observe an inversion of the low temperature dependence for the conductivity of doped GaAs by application of a magnetic field. This inversion happens when Wct = 1, as predicted by Houghton (PRB25, 2196, 1982) for the correction to conductivity due to screened Coulomb repulsion in the diffusive regime. This correction follows the oscillating behavior of the transport elastic time entering the Shubnikov-de Haas regime. For Wct > 1, we observe that the Hartree part of the interaction correction is suppressed. Moreover, the total correction seems strongly reduced although its dependence stays logarithmic.