Strain-induced resistance anisotropy of GaAs two-dimensional electrons*

We report strain-dependent low temperature magnetotransport measurements of two-dimensional electrons confined in GaAs single quantum wells. The samples are mounted to a piezoelectric-based strain device with which we can apply, and vary, tensile strain in the quantum well in situ. With this apparatus we have achieved strain as large as ~0.3% in GaAs quantum wells at cryogenic temperatures. We find that with increasing strain the magnetoresistance of the two-dimensional electron system confined in the quantum well becomes anisotropic relative to the principle in-plane axes of the host crystal. Additionally, we find that this strain-induced resistance anisotropy exhibits hysteresis in the vicinity of Landau Level filling factor ν=5/2.