Superlattice effects induced by atomic ordering onGaxIn1−

Optical properties of highly disordered InGaP by solid-source molecular beam epitaxy with a GaP decomposition source

“…3(a). Besides LO 1 (GaP-like, B383 cm À1 ), and LO 2 (InP-like, B361 cm À1 ), TO 2 (InP-like, B332 cm À1 ) is a weak mode and TO 1 (GaP-like) is hided by LO 2 since it is at the same Raman inactive in (0 0 1) crystal and at a frequency very closed to LO 2 (just above it) [14,20]. It is clearly observed from Fig.…”

“…The InGaP alloy grown on nominally (0 0 1)-oriented GaAs substrates normally yields the CuPt structure with 1 1 1 h i ordering planes, i.e., gives rise to a superlattice of alternating Ga rich (Ga 1+Z In 1ÀZ P 2 ) and In rich (Ga 1ÀZ In 1+Z P 2 ) alloy monlayers perpendicular to this axis [14]. Superperiodicity along the ordering direction lowers the symmetry from cubic ðT d Þ to rhombohedral ðC 3v Þ; and the resultant halving of the Brillouin zone leads to the folding of the conduction band at the L point of the original material to the zone center of the ordered alloy.…”

Effects of the orientational superlattice on the electronic and vibrational properties of CuPt ordered GaInP alloys

“…17,19,20 In double-variant order samples, an extra peak at ¾219 cm 1 has been observed and explained as a folded LA(X) phonon due to the OSL effect. 15 However, the 354 cm 1 peak was not seen in the double-variant ordered samples studied in Ref.…”

“…GaP-like LO  , the 364 cm 1 InP-like LO  and the ¾330 cm 1 InP-like TO  phonons, the 354 cm 1 CuPt ordering induced folded LO mode is clearly seen 17,19,20. For…”

Optical observation of twinning patterns characteristic ofCuPtBatomic ordering inGa1

“…6,7 It results in the spontaneous formation of a shortperiod superlattice along a particular crystallographic direction, with a simultaneous reduction of the symmetry of the point group of the crystal. This reduction of symmetry is actually equivalent to a spontaneous deformation similar to that occurring in ferroelastic crystals.…”