Coexistence of large conventional and planar spin Hall effect with long spin diffusion length in a low-symmetry semimetal at room temperature

• Published in: Nature materials 2020-03, Vol.19 (3), p.292-298
• Main Authors: Song, Peng, Hsu, Chuang-Han, Vignale, Giovanni, Zhao, Meng, Liu, Jiawei, Deng, Yujun, Fu, Wei, Liu, Yanpeng, Zhang, Yuanbo, Lin, Hsin, Pereira, Vitor M., Loh, Kian Ping
• Format: Article
• Language: English
• Subjects: 639/301/1005/1007; 639/925/357/1018; 639/925/357/995; Biomaterials; Chemistry and Materials Science; Condensed Matter Physics; Crystals; Diffusion effects; Diffusion layers; Diffusion length; Electromagnetism; Hall effect; Linear polarization; Materials Science; Molybdenum compounds; Nanotechnology; Optical and Electronic Materials; Polarization (spin alignment); Room temperature; Spin-orbit interactions; Spintronics; Symmetry; Tellurides; Transport
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-019-0600-4

The spin Hall effect (SHE) is usually observed as a bulk effect in high-symmetry crystals with substantial spin–orbit coupling (SOC), where the symmetric spin–orbit field imposes a widely encountered trade-off between spin Hall angle ( θ SH ) and spin diffusion length ( L sf ), and spin polarization, spin current and charge current are constrained to be mutually orthogonal. Here, we report a large θ SH of 0.32 accompanied by a long L sf of 2.2 μm at room temperature in a low-symmetry few-layered semimetal MoTe 2 , thus identifying it as an excellent candidate for simultaneous spin generation, transport and detection. In addition, we report that longitudinal spin current with out-of-plane polarization can be generated by both transverse and vertical charge current, due to the conventional and a newly observed planar SHE, respectively. Our study suggests that manipulation of crystalline symmetries and strong SOC opens access to new charge-spin interconversion configurations and spin–orbit torques for spintronic applications. A large spin Hall angle and long spin diffusion length are found in the low-symmetry, few-layer semimetal MoTe 2 at room temperature, thus identifying this material as an excellent candidate for simultaneous spin generation, transport and detection.