Kang Jing, Zou Jianfei, Li Kai, Yu Shun-Li, Shao Lu-Bing
College of Science, Hohai University, Nanjing, 210098, China.
School of Physics and Engineering, Zhengzhou University, Zhengzhou, 450001, China.
Sci Rep. 2019 Feb 26;9(1):2824. doi: 10.1038/s41598-019-39258-3.
The quasiparticle spectra of interacting Weyl and nodal-line semimetals on a cubic lattice are studied using the cluster perturbation theory. By tracking the spectral functions under interaction, we find that the Weyl points will move to and meet at a specific point in one Weyl semimetal model, while in the other Weyl semimetal model they are immobile. In the nodal-line semimetals, we find that the nodal line shrinks to a point and then disappears under interaction in one-nodal-line system. When we add another nodal line to this system, we find that the two nodal lines both shrink to specific points, but the disappearing processes of the two nodal lines are not synchronized. We argue that the nontrivial evolution of Weyl points and nodal lines under interaction is due to the presence of symmetry breaking order, e.g., a ferromagnetic moment, in the framework of mean field theory, whereas the stability of Weyl points under interaction is protected by symmetry. Among all these models, the spectral gap is finally opened when the interaction is strong enough.
利用团簇微扰理论研究了立方晶格上相互作用的外尔半金属和节线半金属的准粒子能谱。通过追踪相互作用下的能谱函数，我们发现在一个外尔半金属模型中，外尔点会移动并在一个特定点相遇，而在另一个外尔半金属模型中它们是固定不动的。在节线半金属中，我们发现在单节线系统中，节线在相互作用下会收缩到一个点然后消失。当我们向这个系统添加另一条节线时，我们发现两条节线都会收缩到特定点，但两条节线的消失过程并不同步。我们认为，在平均场理论框架下，相互作用下外尔点和节线的非平凡演化是由于对称性破缺序（例如铁磁矩）的存在，而相互作用下外尔点的稳定性则由对称性保护。在所有这些模型中，当相互作用足够强时最终会打开能隙。
