SCALING OF THE CONDUCTIVITY OF SI:B: ANOMALOUS CROSSOVER IN A MAGNETIC FIELD

The zero-temperature conductivity of Si:B with dopant concentrations near the metal-insulator transition exhibits scaling as a function of magnetic field with an anomalously large crossover exponent. The large value of δ is associated with unusual behavior of the magnetoconductance, which vanishes as a power law approaching the transition. This demonstrates that Si:B, which has an anomalous critical conductivity exponent in zero field, also exhibits unusual behavior in response to a magnetic field. 1 Based on a number of experimental results, most notably the elegant measurements to very low temperatures by Paalanen et al. 1 in stress-tuned Si:P, the metal-insulator transition that occurs in doped semiconductors and amorphous metal-semiconductor mixtures is generally believed to be a continuous phase transition. 2 Various physical properties, such as the conductivity and the Hall coefficient, are expected to satisfy appropriat