Quantum behavior of coherent optical phonons

相干光学声子的量子行为

基本信息

批准号：
17540305
负责人：
ISHIOKA Kunie
金额：
$ 2.24万
依托单位：
National Institute for Materials Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

The present study has conducted experimental investigation on quantum interference of coherent optical phonons in semiconductors and semimetals under high-density photo excitation. The author and the coworkers had shown in the previous studies a striking amplitude collapse-revival of coherent symmetric phonons of semimetal Bi. In the present study, the author have performed a detailed and systematic pump-probe experiments on the symmetric and asymmetric phonon modes of Bi, as well as on phonon modes in other semiconductors and semimetals. The obtained experimental results lead to conclude that(1)the generation of coherent phonons is not solely dominated by "Displacive Excitation", as it was considered for more than a decade, but is substantially contributed by stimulated Raman process. The amplitude collapse-revival is attributed to dynamic quantum interference between phononic and electronic states (Fano effect).(2)the sub-linear power dependence of the phonon amplitude of CdTe is explained, from comparison with GaAs and Ge, to be due to the saturation of transient electric field screening at the surface.(3)sub-10 fs laser pulses excites and probes the 40 THz coherent optical phonon in single crystal diamond. The coherent phonons are driven by electric field via resonant stimulated Raman process, without creating photo excited carriers.These results demonstrate that a simple pump-probe reflectivity experiments provide a powerful tool to investigate the ultra fast dynamics of high-frequency phonons in solid materials in semiconductors and insulators, as well as their interaction with photo-excited carriers.

本研究已经对高密度的光激发下半导体和半学的相干光语音子的量子干扰进行了实验研究。作者和同事在先前的研究中表明，半含量BI的相干对称声子的显着振幅崩溃了。在本研究中，作者对BI的对称和非对称声子模式以及其他半导体和半学分的声子模式进行了详细的系统泵探针实验。获得的实验结果得出的结论是，（1）相干声子的产生不仅由“位移激发”主导，因为它被认为已有十多年了，但由刺激的拉曼过程大大贡献。 The amplitude collapse-revival is attributed to dynamic quantum interference between phononic and electronic states (Fano effect).(2)the sub-linear power dependence of the phonon amplitude of CdTe is explained, from comparison with GaAs and Ge, to be due to the saturation of transient electric field screening at the surface.(3)sub-10 fs laser pulses excites and probes the 40 THz coherent optical phonon in single水晶钻石。相干的声子由电场通过谐振刺激的拉曼工艺驱动，而不会创建照片激发载体。这些结果表明，简单的泵送反射性实验提供了一种强大的工具，可以调查半导体和绝缘子中固体材料的超快速音量的超快速动态，以及与照片相互作用，以及它们的相互作用。