Picosecond strain dynamics in Ge2Sb2Te5 monitored by time-resolved x-ray diffraction

Article

关键词: MEMORY MATERIALS;    OPTICAL MEMORY;    PHONONS;    MEDIA;    FILMS;   

DOI  :  10.1103/PhysRevB.90.094305

来源: SCIE

【 摘 要 】

Coherent phonons (CPs) generated by laser pulses on the femtosecond scale have been proposed as a means to achieve ultrafast, nonthermal switching in phase-change materials such as Ge2Sb2Te5 (GST). Here we use ultrafast optical pump pulses to induce coherent acoustic phonons and stroboscopically measure the corresponding lattice distortions in GST using 100-ps x-ray pulses from the European Synchrotron Radiation Facility (ESRF) storage ring. A linear-chain model provides a good description of the observed changes in the diffraction signal; however, the magnitudes of the measured shifts are too large to be explained by thermal effects alone, implying the presence of excited-state effects in addition to temperature-driven expansion. The information on the movement of atoms during the excitation process can lead to greater insight into the possibilities of using CP-induced phase transitions in GST.

【 授权许可】

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