We　fabricated　the　amorphous　GeTe/cubic　Sb2Te3　supperlattice-like　structure　films　by　the　radio　frequency　sputtering,　and　demonstrated　the　stability　of　cubic　Sb2Te3　could　be　strengthened.　The　competition　between　interface　energy　and　phase　transformation　energy　resulted　in　the　thermodynamical　stability　at　the　nanoscale.　The　presented　design　approach　opens　the　doors　for　the　stabilization　of　metastable　phase,　and　sheds　new　insights　into　the　role　of　interfaces　in　materials　synthesis.　(C)　2019　Elsevier　B.V.　All　rights　reserved.