Characteristics of Sb_6Te_4/VO_2 Multilayer Thin Films for Good Stability and Ultrafast Speed Applied in Phase Change Memory

The Sb_6Te_4/VO_2 multilayer thin films are prepared by magnetron sputtering and the potential application in phase change memory is investigated in detail. Compared with Sb_6Te_4, Sb_6Te_4/VO_2 multilayer composite thin films have higher phase change temperature and crystallization resistance, indicating better thermal stability and less power consumption. Also, Sb_6Te_4/VO_2 has a broader energy band of 1.58 eV and better data retention(125℃ for 10 y). The crystallization is suppressed by the multilayer interfaces in Sb_6Te_4/VO_2 thin film with a smaller rms surface roughness for Sb_6Te_4/VO_2 than monolayer Sb_4Te_6. The picosecond laser technology is applied to study the phase change speed. A short crystallization time of 5.21 ns is realized for the Sb_6Te_4(2 nm)/VO_2(8 nm)thin film. The Sb_6Te_4/VO_2 multilayer thin film is a potential and competitive phase change material for its good thermal stability and fast phase change speed.     

两类光合作用系统能量传输过程中的动力学演化

为了获得两类光合作用系统Fenna-Matthews-Olson(FMO)和Phycoerythrin545(PE545)在能量传输过程中的动力学演化,首先通过对Ohmic、Debye和Adolphs and Renger(AR)谱密度进行参量化计算,然后将计算结果应用到TNL(时间非局域)方法中,计算出FMO和PE545的动力学演化过程.结果表明,Ohmic、Debye和AR谱密度参量化后的结果与原谱密度在足够大的频率范围内吻合,而且对比其他方法计算的FMO和PE545的动力学演化过程,该方法计算得到的结果足够精确,其对满足TNL方法要求的可参量化的谱密度函数的扩展是正确的,可用于光合系统的动力学计算.