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

Peng Song; Chuang-Han Hsu; Giovanni Vignale; Meng Zhao; Jiawei Liu; Yujun Deng; Wei Fu; Yanpeng Liu; Yuanbo Zhang; Hsin Lin; Vitor M Pereira; Kian Ping Loh

doi:10.1038/s41563-019-0600-4

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

Nat Mater. 2020 Mar;19(3):292-298. doi: 10.1038/s41563-019-0600-4. Epub 2020 Feb 3.

Authors

Peng Song^#^{1

2}, Chuang-Han Hsu^#^{1

3}, Giovanni Vignale^{4

5}, Meng Zhao⁶, Jiawei Liu^{1

3}, Yujun Deng⁷, Wei Fu^{1

2}, Yanpeng Liu^{1

2}, Yuanbo Zhang⁷, Hsin Lin⁸, Vitor M Pereira^{9

10}, Kian Ping Loh^{11

12}

Affiliations

¹ Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
² Department of Chemistry, National University of Singapore, Singapore, Singapore.
³ Department of Physics, National University of Singapore, Singapore, Singapore.
⁴ Yale-NUS College, Singapore, Singapore.
⁵ Department of Physics, University of Missouri, Columbia, MO, USA.
⁶ Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Innovis, Singapore, Singapore.
⁷ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
⁸ Institute of Physics, Academia Sinica, Taipei, Taiwan. [email protected].
⁹ Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore. [email protected].
¹⁰ Department of Physics, National University of Singapore, Singapore, Singapore. [email protected].
¹¹ Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore. [email protected].
¹² Department of Chemistry, National University of Singapore, Singapore, Singapore. [email protected].

^# Contributed equally.

PMID: 32015531
DOI: 10.1038/s41563-019-0600-4

Abstract

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 MoTe₂, 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.

Grants and funding

A1938c0035/Agency for Science, Technology and Research (A*STAR)