非谐性
共振超声光谱学
德拜模型
晶格常数
各向异性
凝聚态物理
从头算量子化学方法
黛比
从头算
声子
光谱学
格子(音乐)
材料科学
化学
物理
弹性模量
热力学
量子力学
衍射
分子
声学
作者
K. Adachi,Hirotsugu Ogi,Akira Nagakubo,Nobutomo Nakamura,Masahiko Hirao,Mamoru Imade,M. Yoshimura,Yoichiro Mori
摘要
Using the antenna-transmission resonant ultrasound spectroscopy, we measured the elastic constants of GaN between 10 and 305 K using 72 resonance frequencies. The mode Grüneisen parameter is determined from temperature dependence of each elastic constant, which is larger along the c axis than along the a axis, showing anisotropy in lattice anharmonicity. The zero-temperature elastic constants, determined using the Einstein-oscillator model, yield the Debye characteristic temperature of 636 K. The ab-initio calculation is carried out for deducing the elastic constants, and comparison between calculations and measurements at 0 K reveals that the local-density-approximation potential is preferable for theoretically evaluating characteristics of GaN. The theoretical calculation also supports the anisotropy in lattice anharmonicity.
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