Ultrafast Carrier-Coupled Interlayer Contraction, Coherent Intralayer Motions, and Phonon Thermalization Dynamics of Black Phosphorus
Ultrafast Carrier-Coupled Interlayer Contraction, Coherent Intralayer Motions, and Phonon Thermalization Dynamics of Black Phosphorus
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DOI：
10.1021/acs.nanolett.2c01019
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发表时间：
2022-06-28
期刊：
影响因子：
10.8
通讯作者：
Yang, Ding-Shyue
中科院分区：
文献类型：
--
作者：
Chebl, Mazhar;He, Xing;Yang, Ding-Shyue
黑磷（bP）具有高度的各向异性性质和动力学行为，即使在二维和货车范德华（vdW）层状材料中也是独特的。在这里，我们表明，层间晶格收缩和协调一致，对称层内振动发生在几个皮秒以下的光注入和弛豫的载流子，使用超快电子衍射的反射几何探测的面外运动。光生载流子和bP的褶皱结构之间的强耦合，与电子能带结构的对齐，是在工作中没有光致相变的这种定向原子运动。三个时间制度可以确定的声子热化动力学，其中没有各向异性的准平衡，达到约50 ps，其次是相干声学声子的传播和热扩散到散装。这里报道的早期的平面外动力学具有重要的意义，单层和几层的bP和其他vdW材料与强电子晶格相关性。
Black phosphorus (bP) exhibits highly anisotropic properties and dynamical behavior that are unique even among two-dimensional and van der Waals (vdW) layered materials. Here, we show that an interlayer lattice contraction and concerted, symmetric intralayer vibrations occur concurrently within few picoseconds following the photoinjection and relaxation of carriers, using ultrafast electron diffraction in the reflection geometry to probe the out-of-plane motions. A strong coupling between the photocarriers and bP's puckered structure, with the alignment of the electronic band structure, is at work for such directional atomic motions without a photoinduced phase transition. Three temporal regimes can be identified for the phonon thermalization dynamics where a quasi-equilibrium without anisotropy is reached in about 50 ps, followed by propagation of coherent acoustic phonons and heat diffusion into the bulk. The early time out-of-plane dynamics reported here have important implications for single-and few layer bP and other vdW materials with strong electronic-lattice correlations.