  Our magnetotransport measurements of quantum Hall stripes in a high-quality
GaAs quantum well in a slightly tilted magnetic field reveal that the
orientation of stripes can be changed by temperature. Field-cooling and
field-warming measurements, as well as observation of hysteresis at
intermediate temperatures allow us to conclude that the observed
temperature-induced reorientation of stripes is owing to the existence of two
distinct minima in the symmetry-breaking potential. We also find that the
native symmetry-breaking mechanism does not depend on temperature and that
low-temperature magnetotransport data should be treated with caution as they do
not necessarily reveal the true ground state, even in the absence of
hysteresis.
