Shift-current-induced strain waves in LiNbO3 mapped by femtosecond x-ray diffraction
Shift-current-induced strain waves in LiNbO3 mapped by femtosecond x-ray diffraction
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DOI：
10.1103/physrevb.94.104302
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发表时间：
2016-09-19
影响因子：
3.7
通讯作者：
Elsaesser, Thomas
中科院分区：
文献类型：
--
作者：
Holtz, Marcel;Hauf, Christoph;Elsaesser, Thomas
通过飞秒X射线衍射直接映射的晶体晶格的响应，通过双光子体光伏效应在LiNbO 3晶体中诱导的电移位电流。大振幅的声应变波是由压电耦合到电流相关的极化而产生的，而其他机制，如非谐声子-声子耦合和电子-声子耦合通过变形势起次要作用。应变波速度的显著变化作为晶体的c轴、电流流动的方向和入射泵浦脉冲的偏振之间的相对取向的函数而发生。观察到的行为是相关的一大类铁电体。
The response of the crystal lattice to an electric shift current induced via the two-photon bulk-photovoltaic effect in a lithium niobate (LiNbO3) crystal is directly mapped by femtosecond x-ray diffraction. Acoustic strain waves of large amplitude are generated by piezoelectric coupling to the current-related polarization while other mechanisms such as anharmonic phonon-phonon couplings and electron-phonon coupling through deformation potentials play a minor role. A striking variation of the strain wave speed occurs as a function of the relative orientation between the crystal's c-axis, the direction of the current flow, and the polarization of the incident pump pulse. The observed behavior is relevant for a large class of ferroelectrics.