Yang H F, Yang L X, Liu Z K, Sun Y, Chen C, Peng H, Schmidt M, Prabhakaran D, Bernevig B A, Felser C, Yan B H, Chen Y L
School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, People's Republic of China.
ShanghaiTech Laboratory for Topological Physics, 201210, Shanghai, People's Republic of China.
Nat Commun. 2019 Aug 2;10(1):3478. doi: 10.1038/s41467-019-11491-4.
Surface Fermi arcs (SFAs), the unique open Fermi-surfaces (FSs) discovered recently in topological Weyl semimetals (TWSs), are unlike closed FSs in conventional materials and can give rise to many exotic phenomena, such as anomalous SFA-mediated quantum oscillations, chiral magnetic effects, three-dimensional quantum Hall effect, non-local voltage generation and anomalous electromagnetic wave transmission. Here, by using in-situ surface decoration, we demonstrate successful manipulation of the shape, size and even the connections of SFAs in a model TWS, NbAs, and observe their evolution that leads to an unusual topological Lifshitz transition not caused by the change of the carrier concentration. The phase transition teleports the SFAs between different parts of the surface Brillouin zone. Despite the dramatic surface evolution, the existence of SFAs is robust and each SFA remains tied to a pair of Weyl points of opposite chirality, as dictated by the bulk topology.
表面费米弧（SFAs）是最近在拓扑外尔半金属（TWSs）中发现的独特的开放费米面（FSs），与传统材料中的封闭费米面不同，它能引发许多奇异现象，如异常的SFA介导的量子振荡、手征磁效应、三维量子霍尔效应、非局域电压产生和异常电磁波传输。在此，通过使用原位表面修饰，我们展示了在典型的TWS——NbAs中成功操控了SFAs的形状、大小甚至连接方式，并观察到它们的演化导致了一种并非由载流子浓度变化引起的异常拓扑里夫希茨转变。该相变使SFAs在表面布里渊区的不同部分之间瞬移。尽管表面发生了显著演化，但SFAs的存在是稳健的，并且每个SFA仍与一对具有相反手征性的外尔点相连，这由体拓扑结构决定。
