Ab initio study on hexagonal Ge₂Sb₂Te₅- A phase-change material for nonvolatile memories

On the basis of ab initio total energy calculations, we have performed an extensive study on the stacking sequence and random occupation of Ge and Sb to make the same layer in stable hexagonal Ge₂Sb₂Te ₅ (h-GST), an excellent candidate for phase change random memory applications. The results demonstrate that the atomic arrangements have great effects on lattice parameter c and electronic properties of h-GST. h-GST changes from semiconductor to metallic behavior as varying the atomic sequence.