Condensed Matter Seminars

Ge2Sb2Te5 (GST-225) is a phase change material which has wide use in fabricating random access memories. With different quenching process, the GST-225 could have three different phases: an amorphous phase, an intermediate cubic phase, a crystalline hexagonal phase. The fast transition between amorphous and crystalline phase makes GST-225 an ideal material for RAM with fast speed. In our project, the Se-doped GST-225 materials are grown and studied. At x=0.9 in liquid nitrogen quenched samples, we observe a phase transition from crystalline to amorphous. The transport measurement also confirm that there are metal-insulator transition happen for both furnace cooled samples and liquid N2 quenched samples at this limit. A tentative hypothesis is proposed to explain this metal-insulator transition.