Ab initio investigation of the anomalous phonon softening in FeSi
Ab initio investigation of the anomalous phonon softening in FeSi
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FeSi 中反常声子软化的从头算研究
DOI：
10.1103/physrevb.94.144304
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发表时间：
2016
影响因子：
3.7
通讯作者：
G. K. H. Madsen
中科院分区：
文献类型：
--
作者：
R. Stern;G. K. H. Madsen
FeSi中声学声子峰的反常软化现象最近引起了实验的广泛关注。在我们的工作中，我们采用密度泛函理论研究了热无序对FeSi的晶格动力学和窄带隙填充的影响。我们表明，通过比较的声子密度的状态，从温度无关的和温度相关的力常数，热结构的无序与热膨胀一起解释了强烈的重整化的声学声子。此外，我们发现一个复杂的热无序和体积之间的相互作用，在间隙关闭。
The anomalous softening of the acoustic phonon peak in FeSi has recently received considerable experimental attention. In our work, we investigate the effect of thermal disorder on the lattice dynamics and the filling of the narrow band gap of FeSi using density functional theory. We show, by comparing the phonon density of states from temperature-independent and temperature-dependent force constants, that thermal structural disorder together with thermal expansion explains the anomalously strong renormalization of the acoustic phonons. Furthermore, we find an intricate interplay between thermal disorder and volume in gap closure.