Spontaneously orderedGa0.47In0.53Asgrown on substrates with the (001) surface tilted4°towards{111}Bare studied using spectroscopic methods as well as x-ray diffraction, transmission electron diffraction and dark-field transmission electron microscopy. The single variant ordering is proved by the absence of one class of the ordering induced12{111}Bsuperlattice spots in transmission electron diffraction patterns as well as by the tilted polarization of the photoluminescence emerging from the samples cleaved edge. The temperature dependence of the luminescence peak position shows an anomalous behavior at low temperatures and a strong dependence of the peak position on the excitation power. From low temperature absorption measurements, we find a band gap reduction of 37 meV and a valence band splitting of 13.2 meV. ©1997 American Institute of Physics.