Abstract
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 nonmonotonic evolution with temperature of the scattering intensity and present a model for second-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.
| Original language | English |
|---|---|
| Article number | 044602 |
| Number of pages | 10 |
| Journal | Physical Review Materials |
| Volume | 7 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Apr 2023 |
Funding
Funding Information: We thank Prof. S. Safran (WIS) for the invaluable fruitful discussions that initiated this project. We also acknowledge support of Dr. I. Pinkas (WIS) for help in designing the experimental setup and Dr. L. Segev (WIS) for developing the Raman software. O.Y. acknowledges funding from: the European Research Council starting grant (850041-ANHARMONIC), O.H. acknowledges support from the Swedish Research Council (VR) program 2020-04630. Publisher Copyright: © 2023 American Physical Society.
All Science Journal Classification (ASJC) codes
- General Materials Science
- Physics and Astronomy (miscellaneous)