28 de agosto de 2024
Cuscó, R., Yeste, J., & Muñoz-Sanjosé, V. (2024). Mass and force-constant disorder in the rocksalt O alloy: A Raman scattering study. Physical Review B, 110(7), 75202. https://doi.org/10.1103/PhysRevB.110.075202
Abstract
We present a Raman scattering study of rocksalt Cd1−𝑥Zn𝑥O alloys in the compositional range between 𝑥=0 and 𝑥=0.1. We use the sharp feature in the second-order Raman spectra associated with the transverse acoustic (TA) modes at the 𝐿 point to monitor the effect of alloy disorder on the phonon lifetime. The 2TA(𝐿) peak shows a substantial broadening as the Zn content is increased up to 10%. The rate of increase is significantly higher than that expected from cationic mass fluctuation as predicted by the mean-field coherent potential approximation. Excellent agreement with the experiment is achieved by including the effect of the force-constant fluctuations using the itinerant coherent potential approximation, demonstrating the significant role of the force-constant disorder in limiting the phonon lifetime in the Cd1−𝑥Zn𝑥O alloys.