아래와 같이 세미나를 개최하오니 많이 참석해 주시기 바랍니다. 아 래 제목: Molecular dynamics simulation to study amorphous structure of Ge2Sb2Te5 연사: 한 승 우 교수 (이화여자대학교) 일시: 2009년 6월 17일(수) 오후 3시 장소: Seminar room(31355) on the third floor 초록: The phase-change random access memory (PRAM) is intensively studied as the next-generation nonvolatile memory that will replace the current flash memory. The working principle of PRAM is based on the phase-change phenomena of chacolgenide material, most notably Ge2Sb2Te5, between the crystalline and amorphous phases. The amorphous structure of Ge2Sb2Te5 has been under intensive researches recently. In particular, the molecular dynamics (MD) simulation can directly emulate the phase transition phenomena in the actual device, which occurs over a few nanoseconds. In this presentation, we introduce our recent MD calculations to study the amorphous structures of Ge2Sb2Te5. The amorphous structure is obtained by melt-quenching the liquid Ge2Sb2Te5. We vary the simulation condition such as volume and quenching rate and discuss how the results are affected by these parameters. The analysis on the electronic structure indicates that the energy gap of the amorphous structure increases with the simulation cell volume, which can explain the resistance drift of PRAM. 46627836794662783679