Pressure-induced stacking sequence variations in gold from first principles
Pressure-induced stacking sequence variations in gold from first principles
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DOI：
10.1103/physrevb.88.214110
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发表时间：
2013-12
影响因子：
3.7
通讯作者：
T. Ishikawa;Kuniko Kato;Masaya Nomura;N. Suzuki;H. Nagara;K. Shimizu
中科院分区：
文献类型：
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作者：
T. Ishikawa;Kuniko Kato;Masaya Nomura;N. Suzuki;H. Nagara;K. Shimizu
压力引起的堆叠顺序的变化，金的第一性原理计算预测。在静态条件下，面心立方（fcc）相的ABC堆积在200 GPa以上转变为ABCACB，然后转变为ABAC，对应于双六方密排结构。通过进一步压缩，具有AB堆叠的六方密堆积（hcp）结构成为所有堆叠结构中最稳定的结构。这一系列的转变显示了一个逐步增加的六边形在一个很宽的压力范围。声子自由能的计算表明，介于fcc和hcp之间的中间堆积结构如ABCACB或ABAC的稳定区随温度的升高而变窄，在400 K以上fcc直接转变为hcp。这种从fcc到hcp的直接转变定性地与早期的实验观察相一致。
Pressure-induced stacking sequence variations of gold are predicted from first-principles calculations. At the static condition, the ABC stacking in the face-centered-cubic (fcc) phase changes into ABCACB above at least 200 GPa, and then into ABAC corresponding to the double hexagonal-close-packed structure. By further compression, the hexagonal-close-packed (hcp) structure with the AB stacking emerges as the most stable structure of all the stacking structures. This sequence of the transitions shows a step-by-step increase of the hexagonality over a wide pressure range. The calculations of phonon free energy indicate that the stable region of the intermediate stacking structures between fcc and hcp such as ABCACB or ABAC gets to be narrow with increase of temperature and fcc directly transforms into hcp above 400 K. This direct transition from fcc to hcp is qualitatively consistent with the earlier experimental observations.