Finite size suppression of the weak field magnetoresistance of lightly phosphorous-doped silicon

摘要

We report magnetoresistance measurements of lightly phosphorous doped silicon in samples that are fabricated from silicon-on-insulator wafers and so confined in one dimension. All three principal magnetic field orientations were studied at 50 and 270 K for thicknesses between 1.5-530 μm, and as thin as 150 nm at 270 K. The weak field magnetoresistance was suppressed in the orientations with the field in the sample plane when the sample is thinner than ～1 μm at 270 K (～10 μm at 50 K). This suppression occurred for samples that are much thicker than the carrier mean free path and the Debye screening length, and the relevant lengthscale is instead the energy relaxation length.