中国物理B ›› 2014, Vol. 23 ›› Issue (4): 44206-044206.doi: 10.1088/1674-1056/23/4/044206
• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇 下一篇
徐悦a, 金钻明a b, 张郑兵a, 张泽宇a, 林贤a, 马国宏a, 程振祥c
Xu Yue (徐悦)a, Jin Zuan-Ming (金钻明)a b, Zhang Zheng-Bing (张郑兵)a, Zhang Ze-Yu (张泽宇)a, Lin Xian (林贤)a, Ma Guo-Hong (马国宏)a, Cheng Zhen-Xiang (程振祥)c
摘要: The creation and propagation of longitudinal acoustic phonons (LAPs) in high quality hematite thin films (α-Fe2O3) epitaxially grown on different substrates (BaTiO3, SrTiO3, and LaAlO3) are investigated using the femtosecond pump-probe technique. Transient reflection measurements (ΔR/R) indicate the photo-excited electron dynamics, and the initial decay less than 1 ps and the slow decay of ~ 500 ps are attributed to the electron-LO phonon coupling and electron-hole nonradiative recombination, respectively. LAPs in α-Fe2O3 film can be created by ultrafast excitation of the ligand field state, such as the ligand field transitions under 800-nm excitation as well as the ligand to metal charge-transfer with 400-nm excitation. The strain modulations of the sound velocity and the out-of-plane elastic properties are demonstrated in α-Fe2O3 film on different substrates.
中图分类号: (Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency)