The phonon-drag thermopower in Si:B and Si:Sb δ-doped samples

The thermal conductivity and the thermoelectric power of two dimensional hole and electron gases in B and Sb delta-doped Si structures have been measured for the first time. The temperature range was 1.4 K to 30 K, and carrier sheet densities were in the range 0.3 to 1.0 × 10 14 cm -2 . Kohn anomalies have been observed in all samples. The thermopower is dominated by the phonon drag contribution in each case. Calculations of the temperature dependence of the thermopower agree with experimental data when unscreened phonon scattering potentials are used for Si:B and Si:Sb.