论文标题
基于二晶压的钠离子电池的拓扑狄拉克半学相的阳极材料
Topological Dirac Semimetal Phase in Bismuth Based Anode Materials for Sodium-Ion Batteries
论文作者
论文摘要
由于其较高的容量，Bismuth最近引起了与Na-ion电池阳极有关的兴趣。它与NA反应形成Na $ _3 $ bi，这是一种具有非平凡电子结构的典型狄拉克半学。基于密度功能理论的第一原理计算在理解Na $ _3 $ bi和其他拓扑材料的引人入胜的电子结构方面发挥了关键作用。特别是，强烈约束并明确指定的（扫描）元元化梯度 - 抗氧化（Meta-GGA）在捕获许多材料类别的能量，结构和电子特性的广泛使用的梯度 - 透明度（GGA）方案（GGA）方案中显示出显着改善。在这里，我们在扫描框架中讨论了Na $ _3 $ bi的电子结构，并表明所得的费米速度和{\ it s} -band绕$γ$点周围的{\ it s} - 带移动比相应的GGA预测更好地与实验达成一致性。与早期的GGA结果相反，扫描可产生纯粹的自旋轨道耦合（SOC）驱动的Dirac半学状态。我们的分析揭示了从狄拉克半学到Na $ _ {3} $ _ {3} $ bi $ _ {x} $ sb $ _ {1-x} $合金的拓扑相过渡到微不足道的绝缘体阶段，因为作为社会的强度，与SB的内容不同，并使soc soc the soc the soc the soc the bi bi bi bi bi y nata $ y nata $ y nata $ _3 $ a $ _3 $。
Bismuth has recently attracted interest in connection with Na-ion battery anodes due to its high volumetric capacity. It reacts with Na to form Na$_3$Bi which is a prototypical Dirac semimetal with a nontrivial electronic structure. Density-functional-theory based first-principles calculations are playing a key role in understanding the fascinating electronic structure of Na$_3$Bi and other topological materials. In particular, the strongly-constrained-and-appropriately-normed (SCAN) meta-generalized-gradient-approximation (meta-GGA) has shown significant improvement over the widely used generalized-gradient-approximation (GGA) scheme in capturing energetic, structural, and electronic properties of many classes of materials. Here, we discuss the electronic structure of Na$_3$Bi within the SCAN framework and show that the resulting Fermi velocities and {\it s}-band shift around the $Γ$ point are in better agreement with experiments than the corresponding GGA predictions. SCAN yields a purely spin-orbit-coupling (SOC) driven Dirac semimetal state in Na$_3$Bi in contrast with the earlier GGA results. Our analysis reveals the presence of a topological phase transition from the Dirac semimetal to a trivial band insulator phase in Na$_{3}$Bi$_{x}$Sb$_{1-x}$ alloys as the strength of the SOC varies with Sb content, and gives insight into the role of the SOC in modulating conduction properties of Na$_3$Bi.
