Yang Run, Zhang Tan, Zhou Liqin, Dai Yaomin, Liao Zhiyu, Weng Hongming, Qiu Xianggang
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Phys Rev Lett. 2020 Feb 21;124(7):077403. doi: 10.1103/PhysRevLett.124.077403.
The discovery of magnetic Weyl semimetal (magnetic WSM) in Co_{3}Sn_{2}S_{2} has triggered great interest for abundant fascinating phenomena induced by band topology conspiring with the magnetism. Understanding how the magnetization affects the band structure can give us a deeper comprehension of the magnetic WSMs and guide us for the innovation in applications. Here, we systematically study the temperature-dependent optical spectra of ferromagnetic WSM Co_{3}Sn_{2}S_{2} experimentally and simulated by first-principles calculations. Our results indicate that the many-body correlation effect due to Co 3d electrons leads to the renormalization of electronic kinetic energy by a factor about 0.43, which is moderate, and the description within density functional theory is suitable. As the temperature drops down, the magnetic phase transition happens, and the magnetization drives the band shift through exchange splitting. The optical spectra can well detect these changes, including the transitions sensitive and insensitive to the magnetization, and those from the bands around the Weyl nodes. The results support that, in magnetic WSM Co_{3}Sn_{2}S_{2}, the bands that contain Weyl nodes can be tuned by magnetization with temperature change.
在Co₃Sn₂S₂中发现磁性外尔半金属(magnetic WSM)引发了人们对由能带拓扑与磁性共同作用产生的大量迷人现象的浓厚兴趣。了解磁化如何影响能带结构可以让我们更深入地理解磁性外尔半金属,并指导我们进行应用创新。在此,我们通过实验系统地研究了铁磁WSM Co₃Sn₂S₂的温度依赖光谱,并通过第一性原理计算进行了模拟。我们的结果表明,由于Co 3d电子导致的多体关联效应使电子动能重整化了约0.43倍,这一程度适中,并且密度泛函理论内的描述是合适的。随着温度下降,发生磁相变,磁化通过交换劈裂驱动能带移动。光谱能够很好地检测到这些变化,包括对磁化敏感和不敏感的跃迁,以及来自外尔节点周围能带的跃迁。结果支持,在磁性WSM Co₃Sn₂S₂中,包含外尔节点的能带可以随着温度变化通过磁化进行调控。