Fig. 1
From: Mapping the band structure of GeSbTe phase change alloys around the Fermi level
Structural models of Ge2Sb2Te5 (GST-225). a Metastable rock salt structure: red circles: Te, striped circles: Ge, Sb, or vacancy (Vc); (111) planes are marked with alternating colors (red: Te, turquoise: Ge/Sb/Vc); b DFT-optimized structure of the disordered subsurface layer of a GST-225 slab, blue: Ge, green: Sb; c layer structure of one unit cell of metastable rock salt GST-225 exhibiting ABC stacking; the 2 × 3 layers in the unit cell result from the two chemically distinct layers and the three distinct stacking positions; d same as c, but for the cubic Petrov phase of GST-225 exhibiting a unit cell of 10 × 3 layers with 10 layers due to the alternating chemistry and a threefold repetition due to the ABC stacking
