Observation of strong higher-order lattice anharmonicity in Raman and infrared spectra
Name
PhysRevB.101.161202.pdf
Description
Published version
Size
1.58 MB
Format
Adobe PDF
Checksum (MD5)
5d8eabdcc7b1149b12d067f6e3746ccd
Author(s)
Yang, Xiaolong
Feng, Tianli
Kang, Joon Sang
Hu, Yongjie
Li, Ju
Ruan, Xiulin
Date Issued
2020
Journal
Physical Review B
Publisher
American Physical Society (APS)
Version
Final published version
Abstract
© 2020 American Physical Society. The fundamental theory of Raman and infrared (IR) linewidth has been well established as the third-order lattice anharmonicity (three-phonon scattering). In this work, we use both rigorous density functional calculations and Raman experiments to find, surprisingly, that the fourth-order anharmonicity universally plays a significant or even dominant role over the third-order anharmonicity at room temperature, and more so at elevated temperatures, for a wide range of materials including diamond, Si, Ge, GaAs, boron arsenide (BAs), cubic silicon carbide (3C-SiC), and α-quartz. This is enabled by the large four-phonon scattering phase space of zone-center optical phonons. Raman measurements on BAs were conducted, and their linewidth verifies our predictions. The predicted infrared optical properties through the Lorentz oscillator model, after including four-phonon scattering, show much better agreement with experimental measurements than those three-phonon-based predictions. Our work advances the fundamental understanding of Raman and IR response and will broadly impact spectroscopy techniques and radiative transport.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
https://doi.org/10.1103/PHYSREVB.101.161202
