Anharmonic phonon decay in cubic GaN
Anharmonic phonon decay in cubic GaN
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DOI：
10.1103/physrevb.92.075206
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发表时间：
2015-08
影响因子：
3.7
通讯作者：
R. Cuscó;N. Domènech-Amador;S. Novikov;C. T. Foxon;L. Artús
中科院分区：
文献类型：
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作者：
R. Cuscó;N. Domènech-Amador;S. Novikov;C. T. Foxon;L. Artús
我们提出了一个拉曼散射的温度范围从80至750 K的锌（立方）GaN中的光学声子的研究。实验是在GaAs（001）衬底上用分子束外延生长的高质量立方GaN薄膜上进行的。观察到的光学声子的频率和线宽的温度依赖性进行了分析的非谐衰减理论的框架，并讨论了可能的衰减通道的光密度泛函理论计算。LO模式弛豫被发现发生通过不对称衰减到声学声子，具有可观的贡献的高阶过程。TO模线宽表现出较弱的温度依赖性，其频率下移主要由晶格热膨胀决定。由观测到的拉曼谱线宽度导出了LO声子寿命，并与以前的理论预测进行了比较
We present a Raman scattering study of optical phonons in zincblende (cubic) GaN for temperatures ranging from 80 to 750 K. The experiments were performed on high quality, cubic GaN films grown by molecular beamepitaxy on GaAs (001) substrates. The observed temperature dependence of the optical phonon frequencies and linewidths is analyzed in the framework of anharmonic decay theory, and possible decay channels are discussed in the light of density-functional theory calculations. The LO mode relaxation is found to occur via asymmetric decay into acoustic phonons, with an appreciable contribution of higher order processes. The TO mode linewidth shows a weak temperature dependence and its frequency downshift is primarily determined by the lattice thermal expansion. The LO phonon lifetime is derived from the observed Raman linewidth and an excellent agreement with previous theoretical predictions is found