X-ray study of the modulated structure in as-grown Ga2Te3 crystals with the defect zinc-blende lattice

Ga2Te3 crystallizes in the zinc-blende structure, where one third of the cation sites are vacant. Single crystal X-ray diffraction studies were done on as-grown Ga2Te3 crystals. The diffraction measurements show, other than the zinc-blende type main reflections, satellite reflections at q≈1/20(210)c, where the subscript c means the cubic sub-lattice. The analysis of the satellite reflections shows that the crystal contains a two-dimensional modulation with q1≈1/20(210)c   and q1′≈1/20(21¯0)c. The modulated structure is composed of a coupled mode of the amplitude type modulation caused by Ga vacancies and the accompanying displacive modulation of surrounding Te atoms, which has the polarization vector along the [001]c direction. The nature of the atomic modulations is argued and the origin of the modulation is ascribed to the local distortion around a Ga vacancy.

Graphical AbstractGa2Te3 crystallizes into the zinc-blende structure, where one third of the cation sites are vacant. Single crystal X-ray diffraction studies showed that as-grown Ga2Te3 crystals display main reflections which correspond to the cubic zinc-blende lattice and satellite reflections at q=(0.089 0.050 0.00)c. These satellite reflections show that Ga2Te3 crystals contain transverse type displacement modulation, whose traveling direction is almost 〈210〉c, while the polarization vector is nearly 〈001〉cFigure optionsDownload as PowerPoint slide