Spin-polarized gap in the magnetic Weyl semimetal Co<sub>3</sub>Sn<sub>2</sub>S<sub>2</sub>
ORAL
Abstract
We report a unique type of gap in a magnetic Weyl semimetal Co3Sn2S2 where the electrons are spin polarized and preserve the spin-momentum locking feature of Weyl fermions. Such spin-polarized gaps are associated with the Weyl node annihilation, where a pair of Weyl nodes with opposite chirality touch each other at ∼210 meV above the Fermi energy. These are revealed by both time- and spin-resolved ultrafast spectroscopy experiments, combined with first-principles calculations. The spin-polarized gap opening is accompanied by a topological phase transition, and the gap magnitude exhibits an unconventional temperature dependence originated from the Weyl physics. Furthermore, we propose possible circularly polarized terahertz-midinfrared radiation from such a spin-polarized gap. Our results shed light on exploring the topological properties of excited states and endow application potentials for gapped materials based on chirality.
*National Key Research and Development Program of China (Grants No. 2017YFA0303603, No. 2017YFA0302901, No. 2016YFA0300300, and No. 2018YFA0305700), National Natural Science Foundation of China (Grants No. 11774408, No. 11774399, and No. 11925408), Strategic Priority Research Program of CAS (Grants No. XDB30000000 and No. XDB33000000), International Partnership Program of Chinese Academy of Sciences (GJHZ1826), Beijing Natural Science Foundation (4191003), and CAS Interdisciplinary Innovation Team.
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Publication: F. Sun, Jimin Zhao* et al., Spin-polarized gap in the magnetic Weyl semimetal Co3Sn2S2, Phys. Rev. B 104, L100301 (2021).
Presenters
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Fei Sun
- Institute of Physics, Chinese Academy of Sciences
- Max Planck Institute for Chemical Physics of Solids