arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1707.03075cond-mat.mtrl-sci
收藏

对“二维硅烯和锗烯中的电子-声子耦合”一文的评论

Comment on "Electron-phonon coupling in two-dimensional silicene and germanene"

M. E. Cifuentes-Quintal, O. de la Peña-Seaman, R. de Coss

备注：
Accepted for publication in Physical Review B (7 July 2017)
发表信息：
Physical Review B 96, 047401 (2017)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

在他们的工作中，Yan等人[Phys.Rev.B88，121403（2013）]采用密度泛函微扰理论（DFPT）计算，证明与石墨烯相比，硅烯和锗烯在$Γ$ - $E_g$和$K$ - $A_1$声子模式中显示出较弱的Kohn异常。此外，他们使用冻结声子方法计算电子声子（e-ph）耦合矩阵元，并发现在硅烯中费米表面上的平均e-ph耦合矩阵元平方$\langle g_{{\bf q}ν}^2\rangle_{F}$约为石墨烯的50%，但在锗烯中较弱，几乎可以忽略不计。然而，Yan等人认为，硅烯中较小的费米速度补偿了降低的$\langle g_{{\bf q}ν}^2\rangle_{F}$，导致声子线宽（$γ_{{\bf q}ν}$）略大于石墨烯中的声子线宽。本文指出，DFPT和Yan等人对硅烯的冻结声子结果是不一致的。此外，我们已经评估了e-ph耦合使用直接DFPT计算，分析关系，和冻结声子计算，我们系统地发现，$\langle g_{{\bf q}ν}^2\rangle_{F}$和$γ_{{\bf q}ν}$在硅烯是一个数量级小于石墨烯，在严等人的结论相反。

英文摘要：

In their work, Yan et al. [Phys. Rev. B 88, 121403 (2013)] employing density functional perturbation theory (DFPT) calculations, demonstrate that silicene and germanene show weaker Kohn anomalies in the $Γ$-$E_g$ and $K$-$A_1$ phonon modes, compared to graphene. Furthermore, they compute the electron phonon (e-ph) coupling matrix elements using the frozen phonon approach and found that in silicene the average e-ph coupling matrix-element square over the Fermi surface, $\langle g_{{\bf q}ν}^2\rangle_{F}$, is about 50 % of those in graphene, but in germanene is weaker and nearly negligible. However, Yan et al. argues that the smaller Fermi velocity in silicene compensates the reduced $\langle g_{{\bf q}ν}^2\rangle_{F}$, leading to phonon linewidths ($γ_{{\bf q}ν}$) slightly larger than those in graphene. In this Comment, we show that the DFPT and the frozen phonon results of Yan et al. for silicene are inconsistent. Additionally, we have evaluated the e-ph coupling using direct DFPT calculations, analytical relations, and frozen phonon calculations, and we found systematically that $\langle g_{{\bf q}ν}^2\rangle_{F}$ and $γ_{{\bf q}ν}$ in silicene are one order of magnitude smaller than in graphene, in contrast to the conclusions of Yan et al.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑