npj: Dirac半金属预测—新材料发现
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
由于晶体结构、组分原子和能带拓扑之间的关系复杂且难以捉摸,要预测新的Dirac半金属及其他拓扑材料,挑战性极大。
来自复旦大学的张浩和中国科学院物理所的翁红明(本刊编委、学术编辑)教授等科研人员,基于化学自由度的第一原理计算,建立了一种寻找新的令人振奋的Dirac半金属材料的方法,拓展了之前的理论预测。他们从已知Dirac半金属材料Na3Bi开始,在计算上改变化学成分,同时保持晶体和电子结构尽可能接近原始化合物,挑选出了同一家族材料中的三种含Na三元化合物:Na2MgSn, Na2MgPb和Na2CdSn作为候选材料。他们进一步确定了有助于预测材料是否会出现能带反转,即判断是否具有拓扑特性的关键化学规则,从而发现其中的Na2MgPb和Na2CdSn具有Dirac半金属的能带拓扑。在它们的(100)和(010)表面上具有拓扑非平庸表面态,即连接体Dirac点投影的费米弧。重要的是,候选化合物是动力学稳定的且已被实验合成过。他们研究所提出的思想方法可启发人们对其他拓扑材料的计算预测。
该文近期发表于npj Computational Materials 4: 68 (2018),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。
Predicting Dirac semimetals based on sodium ternary compounds
Bo Peng, Changming Yue, Hao Zhang, Zhong Fang & Hongming Weng
Predicting new Dirac semimetals, as well as othertopological materials, is challenging since the relationship between crystalstructure, component atoms and band topology is complex and elusive. Here, wedemonstrate an approach to design Dirac semimetals via exploring chemicaldegree of freedom. Based on understanding of the well-known Dirac semimetal, Na3Bi,three compounds in one family, namely Na2MgSn, Na2MgPb,and Na2CdSn, are located. Furthermore, hybrid-functionalcalculations with improved accuracy for estimation of band inversion show thatNa2MgPb and Na2CdSn have the band topology of Diracsemimetals. The nontrivial surface states with Fermi arcs on the (100) and(010) surfaces are shown to connect the projection of bulk Dirac nodes. Mostimportantly, the candidate compounds are dynamically stable and have beenexperimentally synthesized. The ideas in this work could stimulate furtherpredictions of topological materials based on understanding of existing ones.
扩展阅读
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