[23a-B201-1~12] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

▲ [23a-B201-8] Observation of spin polarization of Weyl semimetal, WTe₂, at room temperature

〇(M2)Kosuke Ohnishi¹, Motomi Aoki¹, Ei Shigematsu¹, Ryo Ohshima¹, Yuichiro Ando^1,2, Taishi Takenobu³, Masashi Shiraishi¹ (1.Kyoto Univ., 2.PRESTO, JST, 3.Nagoya Univ.)

Keywords:Weyl semimetal, WTe2, Perpendicular magnetic anisotropy

A type-II Weyl semimetal, WTe₂ is receiving great attention in spin physics because of the generation of spin polarization due to fictitious Weyl monopoles. In previous study, in-plane spin polarization originating from the Weyl node was reported by introducing an electrical method even though detection is limited at very low temperature. Meanwhile, the existence of perpendicularly spin polarization (S_z spin polarization) due to local symmetry breaking was suggested, and we attempted to observe S_z spin polarization using an all-electrical method.
Perpendicular magnetic anisotropy (PMA) electrodes and nonmagnetic Pt electrodes were deposited on the mechanically exfoliated WTe₂, and the out-of-plane magnetic field dependence of spin voltages was measured from 5 K to 300 K. As a result, a clear hysteresis attributed to spin accumulation beneath the PMA electrode was observed up to 300 K. A detailed origin of the hysteresis and its supporting evidence will be given in the presentation.