Effect of off-stoichiometry on the thermal conductivity of amorphous GeTe

The reversible phase change of Germanium Telluride (GeTe) is essential for developing advanced non-volatile devices. We investigate off-stoichiometric effect on the thermal and structural properties of amorphous Ge1-delta Te (0 <= delta <= 0.12) via molecular dynamics. The structural optimization due to off-stoichiometry was taken into account with an empirical potential. Our simulated thermal conductivity is in the range of experimental observations. With increasing delta, the thermal conductivity tends to be slightly reduced. Analysis on the coordination number and the bond angle distribution indicates that the off-stoichiometric Ge1-delta Te still retain its ability of rapid phase transition. These results are helpful in reliable device design and modeling.