论文标题
拉曼散射在钙钛矿中的无序起源
The Disorder Origin of Raman Scattering In Perovskites Single Crystals
论文作者
论文摘要
氧化物和卤化物钙钛矿的非谐晶格动力学在其机械和光学特性中起着至关重要的作用。拉曼光谱法是用于研究这些结构动力学的关键方法之一。但是，尽管进行了数十年的研究，但现有的解释仍无法解释观察到的拉曼光谱的温度依赖性。我们以散射强度的温度证明了非单调演化，并为第二阶拉曼散射提供了一个模型，该模型解释了这种独特的趋势。通过调用低频Anharmonic特征，我们能够重现拉曼光谱线形状和集成的强度温度依赖性。数值模拟支持我们对这种低频模式的解释为双孔电势表面的两个最小值之间的过渡。该模型可以应用于其他动态无序的晶体阶段，从而更好地了解结构动力学，从而在功能材料中产生有利的电子，光学和机械性能。
The anharmonic lattice dynamics of oxide and halide perovskites play a crucial role in their mechanical and optical properties. Raman spectroscopy is one of the key methods used to study these structural dynamics. However, despite decades of research, existing interpretations cannot explain the temperature dependence of the observed Raman spectra. We demonstrate the non-monotonic evolution with temperature of the scattering intensity and present a model for 2nd-order Raman scattering that accounts for this unique trend. By invoking a low-frequency anharmonic feature, we are able to reproduce the Raman spectral line-shapes and integrated intensity temperature dependence. Numerical simulations support our interpretation of this low-frequency mode as a transition between two minima of a double-well potential surface. The model can be applied to other dynamically disordered crystal phases, providing a better understanding of the structural dynamics, leading to favorable electronic, optical, and mechanical properties in functional materials.
