期刊
PHYSICAL REVIEW B
卷 71, 期 13, 页码 -出版社
AMERICAN PHYSICAL SOC
DOI: 10.1103/PhysRevB.71.134403
关键词
-
We have observed coherent optical and acoustic phonon generation, which are strongly coupled to the charge-ordering (CO) transition in La1-xCaxMnO3 (x=0.5, 0.58) using femtosecond optical pump-probe spectroscopy. Coherent optical phonons, observed at low temperatures, disappear above the charge-ordering temperature T-CO, while coherent acoustic phonons display the opposite behavior, disappearing gradually below T-CO. Coherent optical phonons are generated by the displacive excitation mechanism where their coupling to the photoexcited charge carriers is enhanced by the structural change corresponding to the CO phase transition. The oscillation frequency for the coherent acoustic phonon depends on the probe wavelength, which is consistent with the propagating strain pulse mechanism. The dramatic change of lattice constants across the charge-ordering transition explains the overall temperature dependence of the coherent acoustic phonon amplitude.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据