Octahedral structure of liquid GeSb2Te4 alloy:: First-principles molecular dynamics study

The structure of liquid GeSb2Te4 alloys is investigated using first-principles molecular dynamics at three densities: the experimental one and two other densities, 7% and 15% lower, respectively. Contrary to what has been reported for amorphous phases, no departure from an octahedral local environment, with bond angles around 90 degrees-95 degrees, is observed. Expanding the liquid results in an increasing distortion of the local environment by a Peierls-like mechanism.