We have studied the potential induced by lateral surface superlattices
deposited on a GaAs/AlGaAs heterostructure as a function of bias and
orientation of the gates. By using the gates to null the total potenti
al, we extracted the contribution to this potential in the absence of
gate bias. Its angular dependence shows that it is dominated by strain
from the gates coupled to the electrons by the piezoelectric effect.
(C) 1997 American Institute of Physics.