Makino Kotaro, Tominaga Junji, Hase Muneaki
Institute of Applied Physics, University of Tsukuba, Tsukuba, Japan.
Opt Express. 2011 Jan 17;19(2):1260-70. doi: 10.1364/OE.19.001260.
A class of chalcogenide alloy materials that shows significant changes in optical properties upon an amorphous-to-crystalline phase transition has lead to development of large data capacities in modern optical data storage. Among chalcogenide phase-change materials, Ge2Sb2Te5 (GST) is most widely used because of its reliability. We use a pair of femtosecond light pulses to demonstrate the ultrafast optical manipulation of atomic arrangements from tetrahedral (amorphous) to octahedral (crystalline) Ge-coordination in GST superlattices. Depending on the parameters of the second pump-pulse, ultrafast nonthermal phase-change occurred within only few-cycles (≈1 picosecond) of the coherent motion corresponding to a GeTe4 local vibration. Using the ultrafast switch in chalcogenide alloy memory could lead to a major paradigm shift in memory devices beyond the current generation of silicon-based flash-memory.
一类硫族化物合金材料在从非晶态到晶态的相变过程中表现出显著的光学性质变化，这推动了现代光学数据存储中大数据容量的发展。在硫族化物相变材料中，Ge2Sb2Te5（GST）因其可靠性而被最广泛地使用。我们使用一对飞秒光脉冲来展示在GST超晶格中从四面体（非晶态）到八面体（晶态）锗配位的原子排列的超快光学操纵。根据第二个泵浦脉冲的参数，超快非热相变仅在对应于GeTe4局部振动的相干运动的几个周期（≈1皮秒）内发生。在硫族化物合金存储器中使用超快开关可能会导致存储设备发生重大的范式转变，超越当前一代基于硅的闪存。
