High field magnetoconductivity of Si inversion layers

The transverse magnetoconductivity (σ_χχ) of electron inversion layers on (100) Si is measured in magnetic fields up to 220 kG at temperatures from 4.2 to 1.6 K. The dependence of σ_χχ on T, H, and the electric field along the inversion layer suggests that immobile electrons between two Landau subbands are to a large extent localized out of the top of the lower subband. Fine structure, which may be indicative of inhomogeneities of electronic origin, is observed in σ_χχ vs electron density.