2. Narrow-channel experimentsWheele

2. Narrow-channel experimentsWheeler et al.38 were the first to use magnetoresistance experiments as a tool to distinguish weak localization from electron-electron interaction effects in narrow Si MOSFETs. As in most subsequent studies, the negative magnetoresistance was entirely attributed to the suppression of weak localization; the cooperon-type contributions from electron-electron interactions were ignored. After subtraction of the weak localization correction, the remaining temperature dependence was found to differ from the simple T−1/2 dependence predicted by the theory for W < lT < l [Eq. (2.51b)]. This was attributed in Ref.38 to temperature-dependent screening at the relatively high temperatures of the experiment. Pooke et al.138 found a nice T−1/2 dependence in similar experiments at lower temperatures in narrow Si accumulation layers and in GaAs-AlGaAs heterostructures.