The　nano　amorphous　interface　is　important　as　it　controls　the　phase　transition　for　data　storage.　Yet,　atomic　scale　insights　into　such　kinds　of　systems　are　still　rare.　By　first-principles　calculations,　we　obtain　the　atomic　interface　between　amorphous　Si　and　amorphous　Sb2Te3,　which　prevails　in　the　series　of　Si-Sb-Te　phase　change　materials.　This　interface　model　reproduces　the　experiment-consistent　phenomena,　i.e.　the　amorphous　stability　of　Sb2Te3,　which　defines　the　data　retention　in　phase　change　memory,　and　is　greatly　enhanced　by　the　nano　interface.　More　importantly,　this　method　offers　a　direct　platform　to　explore　the　intrinsic　mechanism　to　understand　the　material　function:　(1)　by　steric　effects　through　the　atomic　＂channel＇＇　of　the　amorphous　interface,　the　arrangement　of　the　Te　network　is　significantly　distorted　and　is　separated　from　the　p-orbital　bond　angle　in　the　conventional　phase-change　material;　and　(2)　through　the　electronic　＂channel＇＇　of　the　amorphous　interface,　high　localized　electrons　in　the　form　of　a　lone　pair　are　＂projected＇＇　to　Sb2Te3　from　amorphous　Si　by　a　proximity　effect.　These　factors　set　an　effective　barrier　for　crystallization　and　improve　the　amorphous　stability,　and　thus　data　retention.　The　present　research　and　scheme　sheds　new　light　on　the　engineering　and　manipulation　of　other　key　amorphous　interfaces,　such　as　Si3N4/Ge2Sb2Te5　and　C/Sb2Te3,　through　first-principles　calculations　towards　non-volatile　phase　change　memory.