Magneto-thermal conductivity of indium antimonide

Abstract

Measurements of the lattice thermal conductivity of in lium antimonide (n=1014 to 1017 and p=1015 to 1017 cm-3) single crystal samples have been performed in the temperature range of 1.2 to 10°K, and for the lower temperatures in magnetic fields up to 40 KG. A new 8-bit microprocessor controlled system was constructed to make fully automatic measurements under optimised conditions. This enabled thermal conductivity measurements to be made to an accuracy of 2% absolute and 0.1% relative. The zero field results are in good agreement with theory and with previous measurements.

The thermal conductivity of the p-InSb decreased with increase of magnetic field. The acceptor ground state is four fold degenerate and the thermal phonons could only be scattered by transition within the quartet of energy levels. It was found that Ge doped sample (P = 2.8 x 1015 cm -3 at 1.23°K exhibited a broad minimum when the field reached about 40 KG which was due to the first order Zeeman splitting of the acceptor ground state.

Quantum oscillations of thermal conductivity of highly doped n-type samples were observed in a magnetic field. The period of oscillation was the same as the Shubnikov-de liaas oscillation of electrical conductivity and it is shown that the oscillation occurs because the electron-phonon interaction osciliates with magnetic field as the Fermi level crosses successive Landau levels.