Scaling behavior of the Hall coefficient of Si:P at the metal-insulator transition

Measurements of the Hall coefficient R(H)(T, B) of Si:P with P concentration N between 3.54 and 7.0 . 10(18) cm(-3) are reported for the temperature range 0.04 K less than or equal to T less than or equal to 4K and in magnetic fields up to 7T. Even far above the metal-insulator transition (MIT), a sign change of the temperature coefficient similar to the behavior of the conductivity sigma(T) in moderate fields is not observed in R(H)(T). Field and temperature dependence of R(H) both increase as the MIT (at the critical concentration N-c = 3.52 . 10(18)cm(-3)) is approached. A careful extrapolation to T --> 0 and B --> 0 indicates that R(H)(-1) scales to zero as R(H)(-1) similar to\ N - N-c \(mu H) with mu(H) = (0.44+/-0.04) in agreement with previous results.