ULTRA-LOW-TEMPERATURE CONDUCTIVITY IN SILICON DOPED WITH ANTIMONY

The authors measure to low temperatures (10 mK) the conductivity behaviour in high magnetic fields of an Sb-doped Si sample of just-metallic character. The sample had previously been assessed by Long and Pepper (1984) as showing evidence for a new electronic phase. Their measurements further highlight the anomalous low-temperature behaviour, and they discuss the results in the context of a recently published theory of the effect, and in comparison to other magnetoresistance data on silicon-based doped semiconductors. A further possibility emerges from this discussion, in that the anomaly may be appearing under experimental conditions such that the usual limiting mechanism on the conductivity is 'frozen-out' by the high magnetic fields used.