We have measured the energy loss rate as a function of carrier tempera
ture for hot holes in Si/Si0.8Ge0.2 quantum wells with sheet carrier d
ensities in the range (3-7)x10(11) cm(-2) at lattice temperatures of 0
.35 and 2.0 K. Calculations of the energy loss rate for acoustic phono
n deformation potential scattering with coupling constant 4.5 eV show
good agreement with measurement. The deformation potential is consiste
nt with a linear interpolation between the bulk Si and Ge values and i
s in agreement with that deduced from measurements of thermopower in s
imilar samples. In contrast to previous work, we find no evidence for
hole coupling to acoustic phonons via a piezoelectric interaction. (C)
1997 American Institute of Physics.