PHONOCONDUCTIVITY MEASUREMENT OF THE PHONON ABSORPTION BY A 2-DIMENSIONAL HOLE GAS IN A GAAS HETEROJUNCTION

In this paper we describe measurements of the absorption of acoustic p honons from a ballistic heat pulse by a two-dimensional (2D) hole gas in a GaAs/AlxGa1-xAs heterojunction. The phonoconductivity technique w as used, in which the change in the resistance of a device caused by p honon absorption is detected. Direct information regarding the hole-ph onon interaction in a heterojunction is obtained by this method. Measu rements of the phonoconductivity in zero and quantizing magnetic field s were made and compared with the results of numerical calculations of the absorption. In spite of the complicated nature of the 2D hole sub bands and the hole-phonon coupling, we find that, at the hole densitie s and temperatures of these experiments, the theory describing the int eraction of 2D electrons with phonons can be reasonably applied to 2D holes with the appropriate change of the effective mass and other rele vant parameters, and the use of a single effective valence-band deform ation potential. Using our results, we are able to determine the Fang- Howard parameter for the confined holes and the effective mass for hea vy holes in the spin-split lowest subband.