Real spin and pseudospin topologies in the noncentrosymmetric topological nodal-line semimetal CaAgAs
Real spin and pseudospin topologies in the noncentrosymmetric topological nodal-line semimetal CaAgAs
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DOI：
10.1103/physrevb.101.245104
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发表时间：
2020-06-01
影响因子：
3.7
通讯作者：
Uji, Shinya
中科院分区：
文献类型：
--
作者：
Hirose, Hishiro T.;Terashima, Taichi;Uji, Shinya
我们提出了通过 de Haas-van Alphen (dHvA) 效应测量结合从头计算确定的 CaAgAs 自旋分裂费米面的拓扑结构。我们根据 β 和 γ 轨道的 dHvA 振荡确定了环面形节线费米面。前者轨道环绕节点线，而后者则不环绕节点线。尽管如此，两个轨道都发现了不平凡的贝里相。 β 的非平凡相位源自轨道特征，可以表示为围绕节点线旋转的赝自旋。另一方面，伽马相位归因于反对称自旋轨道相互作用引起的真实自旋纹理的涡旋。我们的结果表明，实自旋和赝自旋纹理对于解释非中心对称节点线半金属的电子拓扑都是不可或缺的。
We present the topology of spin-split Fermi surface of CaAgAs as determined by de Haas-van Alphen (dHvA) effect measurements combined with ab initio calculations. We have determined the torus-shaped nodal-line Fermi surface from the dHvA oscillations of beta and gamma orbits. The former orbit encircles the nodal line, while the latter does not. Nevertheless, a nontrivial Berry phase is found for both orbits. The nontrivial phase of beta arises from the orbital characters, which can be expressed as a pseudospin rotating around the nodal line. On the other hand, the phase of gamma is attributed to the vortex of real spin texture induced by an antisymmetric spin-orbit interaction. Our result demonstrates that both the real spin and pseudospin textures are indispensable in interpreting the electronic topology in noncentrosymmetric nodal-line semimetals.