npj:钨的弱非简谐声子散射—源自体心立方结构
海归学者发起的公益学术平台
分享信息,整合资源
交流学术,偶尔风月
来自深圳大学高等研究院的李武研究员课题组,在前期工作基础上,通过对高对称方向上的声子散射分析,发现金属钨的声子反常输运行为跟自身的单质体心立方结构紧密相关。在单质体心立方结构中,声子振动频率在高对称点P和H三重简并,在这些点散射通道被完全抑制,故声子-声子散射率在这些点严格为零。这造成了大的声子热导率并使得电子-声子散射占主导地位,进一步导致声子热导率的反常温度依赖性。而对于包含碱金属在内的其他多数bcc金属,又由于在某些方向的声子频率会远远小于其他方向,在这些高对称点声子散射将不再为零。该工作解释了在单质金属中为什么只有钨等少数几种材料的Lorenz数比理论值有显著差异。
该文近期发表于npj Computational Materials 5: 98 (2019),英文标题与摘要如下,点击左下角“阅读原文”可以自由获取论文PDF。
Body-centered-cubic structure and weak anharmonic phonon scattering in tungsten
Yani Chen, Jinlong Ma, Shihao Wen & Wu Li
It was recently found that the anharmonic phonon–phonon scattering in tungsten is extremely weak at high frequencies, leading to a predominance of electron–phonon scattering and consequently anomalous phonon transport behaviors. In this work, we calculate the phonon linewidths of W along high-symmetry directions from first principles. We find that the weak phonon–phonon scattering can be traced back to two factors. The first is the triple degeneracy of the phonon branches at the P and H points, a universal property of elemental body-centered-cubic (bcc) structures. The second is a relatively isotropic character of the phonon dispersions. When both are met, phonon–phonon scattering rates must vanish at the P and H points. The weak phonon–phonon scattering feature is also applicable to Mo and Cr. However, in other elemental bcc substances like Na, the isotropy condition is violated due to the unusually soft character of the lower transverse acoustic phonon branch along the Γ-N direction, opening emission channels and leading to much stronger phonon–phonon scattering. We also look into the distributions of electron mean-free paths (MFPs) at room temperature in tungsten, which can help engineer the resistivity of nanostructured W for applications such as interconnects.
本文系网易新闻·网易号“各有态度”特色内容
媒体转载联系授权请看下方
最新评论
推荐文章
作者最新文章
你可能感兴趣的文章
Copyright Disclaimer: The copyright of contents (including texts, images, videos and audios) posted above belong to the User who shared or the third-party website which the User shared from. If you found your copyright have been infringed, please send a DMCA takedown notice to [email protected]. For more detail of the source, please click on the button "Read Original Post" below. For other communications, please send to [email protected].
版权声明:以上内容为用户推荐收藏至CareerEngine平台,其内容(含文字、图片、视频、音频等)及知识版权均属用户或用户转发自的第三方网站,如涉嫌侵权,请通知[email protected]进行信息删除。如需查看信息来源,请点击“查看原文”。如需洽谈其它事宜,请联系[email protected]。
版权声明:以上内容为用户推荐收藏至CareerEngine平台,其内容(含文字、图片、视频、音频等)及知识版权均属用户或用户转发自的第三方网站,如涉嫌侵权,请通知[email protected]进行信息删除。如需查看信息来源,请点击“查看原文”。如需洽谈其它事宜,请联系[email protected]。