论文标题
py-nodes：使用Nelder-Mead的单纯形方法在材料中搜索节点的Ab-Initio Python代码
PY-Nodes: An ab-initio python code for searching nodes in a material using Nelder-Mead's simplex approach
论文作者
论文摘要
随着拓扑半学的发现，已经发现，在费米级别附近的乐队接触点非常重要。它们在这些材料中引起了许多令人兴奋的现象。此外，这些点通常称为节点，与这些半学的几种特性有关。因此，非常需要对其坐标的正确估计才能更好地理解这些材料的性质。我们设计了一个名为Py-nodes的基于Python 3的代码，以有效地找到使用第一原理方法中给定材料中存在的节点。代码的当前版本与Wien2k软件包连接。为了对代码进行基准测试，已在一些具有特征性节点的著名材料上进行了测试。其中包括-Taas，著名的Weyl半学$ _3 $ bi，被归类为Dirac Semimetal，Caagas，分类为节点线半含量和Yaupb，据称是非平凡的拓扑半学的。如果是TAA，则从我们的计算中获得了24个节点。在计算手力时，发现获得了具有相等和相反手性的12对节点。此外，对于na $ _3 $ bi，在$ \ boldsymbol {k_3} $方向的$γ$ - 点的任一侧都获得了一对节点。如果是Caagas，则在$ K_z $ = 0平面中获得了几个节点。这些节点在$ k_x $ - $ k_y $ plane中绘制时，形成一个封闭环，通常称为节点线。最后，在Yaupb的情况下，在$γ$ - 点附近获得了大量节点。这些材料获得的结果与不同研究小组进行的先前工作非常匹配。这确保了PY节点代码的可靠性和效率，以估计给定材料中存在的节点。
With the discovery of topological semimetals, it has been found that the band touching points near the Fermi level are of great importance. They give rise to many exciting phenomena in these materials. Moreover, these points, commonly known as nodes, are related to several properties of these semimetals. Thus, the proper estimation of their coordinates is extremely needed for better understanding of the properties of these materials. We have designed a Python 3 based code named PY-Nodes for efficiently finding the nodes present in a given material using first-principle approach. The present version of the code is interfaced with the WIEN2k package. For benchmarking the code, it has been tested on some famous materials which possess characteristic nodes. These include - TaAs, a well-known Weyl semimetal, Na$_3$Bi, which is categorized as Dirac semimetal, CaAgAs, classified as a nodal-line semimetal and YAuPb, which is claimed to be non-trivial topological semimetal. In case of TaAs, 24 nodes are obtained from our calculations. On computing their chiralities, it is found that 12 pairs of nodes having equal and opposite chirality are obtained. Furthermore, for Na$_3$Bi, a pair of nodes are obtained on the either side of $Γ$-point in the $\boldsymbol{k_3}$ direction. In case of CaAgAs, several nodes are obtained in the $k_z$=0 plane. These nodes, when plotted in the $k_x$-$k_y$ plane, form a closed loop which is generally referred to as nodal-line. Finally, in the case of YAuPb, large number of nodes are obtained in the vicinity of $Γ$-point. The results obtained for these materials are in good match with the previous works carried out by different research groups. This assures the reliability and the efficiency of the PY-Nodes code for estimating the nodes present in a given material.
