Non-Abelian braiding of Weyl nodes via symmetry-constrained phase transitions
Non-Abelian braiding of Weyl nodes via symmetry-constrained phase transitions
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DOI：
10.1103/physrevb.105.l081117
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发表时间：
2021-08
影响因子：
3.7
通讯作者：
Siyu Chen;Adrien Bouhon;Robert-Jan Slager;B. Monserrat
中科院分区：
文献类型：
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作者：
Siyu Chen;Adrien Bouhon;Robert-Jan Slager;B. Monserrat
Weyl半金属可以说是无间隙拓扑相的最典型的形式。虽然Weyl节点的稳定性已经被广泛地研究，用它们的拓扑电荷来量化，但最近的兴趣已经转移到操纵这些Weyl节点的位置以进行非阿贝尔编织。为了完成这一编织，有必要使用真实的实验参数改变来驱动重要的Weyl节点运动。我们证明了以某些对称约束为特征的一族相变使得Weyl节点必须进行大量的重组，从一个高对称平面移动到另一个高对称平面。此外，对于具有非平凡Euler类拓扑的节点对的子集，这种重组只能通过与相邻节点的编织过程进行。结果，Weyl节点被迫在布里渊区移动很长一段距离，并编织，所有这些都是由微小的温度变化驱动的，我们用CD$2$Re$2$O$7$说明了这个过程。我们的工作开辟了操作Weyl节点的途径，只需微小的外部参数变化，为实际实现互易空间编织铺平了道路。
Weyl semimetals are arguably the most paradigmatic form of a gapless topological phase. While the stability of Weyl nodes, as quantified by their topological charge, has been extensively investigated, recent interest has shifted to the manipulation of the location of these Weyl nodes for non-Abelian braiding. To accomplish this braiding it is necessary to drive significant Weyl node motion using realistic experimental parameter changes. We show that a family of phase transitions characterized by certain symmetry constraints impose that the Weyl nodes have to reorganise by a large amount, shifting from one high symmetry plane to another. Additionally, for a subset of pairs of nodes with nontrivial Euler class topology, this reorganization can only occur through a braiding process with adjacent nodes. As a result, the Weyl nodes are forced to move a large distance across the Brillouin zone and to braid, all driven by small temperature changes, a process we illustrate with Cd$_2$Re$_2$O$_7$. Our work opens up routes to readily manipulate Weyl nodes using only slight external parameter changes, paving the way for the practical realization of reciprocal space braiding.