Abstract
The thermoelectric power S(T) of metallic compensated Si:(P,B) samples with carrier concentration N = 13.0 and 4.24·1018cm−3 has been measured between 0.1 and 10 K. For the more heavily doped sample, the low-T data can be well described with a negative T-linear nearly-free–electron diffusion term and a T3 phonon-drag contribution. The sample closer to the metal-insulator transition (critical concentration Nc = 3.54·1018cm−3 for the compensation ratio of this sample), exhibits a sign change of S(T) at 0.35 K, becoming positive towards lower T. The ensuing maximum (since S(T → 0) = 0) is attributed to Kondo scattering by local magnetic moments. This is supported by the suppression of this maximum and recovery of a linear S(T) in a magnetic field of ≈ 5 T.