Observation of Thickness-Modulated Out-of-Plane Spin-Orbit Torque in Polycrystalline Few-Layer Td-WTe₂ Film.

IF 4.4 3区材料科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Nanomaterials Pub Date : 2025-05-19 DOI:10.3390/nano15100762

Mingkun Zheng, Wancheng Zhang, You Lv, Yong Liu, Rui Xiong, Zhenhua Zhang, Zhihong Lu

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Abstract

The low-symmetry Weyl semimetallic Td-phase WTe₂ exhibits both a distinct out-of-plane damping torque (τDL) and exceptional charge-spin interconversion efficiency enabled by strong spin-orbit coupling, positioning it as a prime candidate for spin-orbit torque (SOT) applications in two-dimensional transition metal dichalcogenides. Herein, we report on thickness-dependent unconventional out-of-plane τDL in chemically vapor-deposited (CVD) polycrystalline Td-WTe₂ (t)/Ni₈₀Fe₂₀/MgO/Ti (Td-WTN-t) heterostructures. Angle-resolved spin-torque ferromagnetic resonance measurements on the Td-WTN-12 structure showed significant spin Hall conductivities of σ_SH,y = 4.93 × 10³ (ℏ/2e) Ω^-1m^-1 and σ_SH,z = 0.81 × 10³ (ℏ/2e) Ω^-1m^-1, highlighting its potential for wafer-scale spin-orbit torque device applications. Additionally, a detailed examination of magnetotransport properties in polycrystalline few-layer Td-WTe₂ films as a function of thickness revealed a marked amplification of the out-of-plane magnetoresistance, which can be ascribed to the anisotropic nature of charge carrier scattering mechanisms within the material. Spin pumping measurements in Td-WTN-t heterostructures further revealed thickness-dependent spin transport properties of Td-WTe₂, with damping analysis yielding an out-of-plane spin diffusion length of λ_SD ≈ 14 nm.

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多晶少层Td-WTe2薄膜中厚度调制的面外自旋轨道转矩观察。

低对称Weyl半金属td相WTe2表现出明显的面外阻尼扭矩（τDL）和特殊的电荷-自旋相互转换效率，使其成为二维过渡金属二硫族化合物中自旋-轨道扭矩（SOT）应用的主要候选者。本文报道了化学气相沉积（CVD）多晶Td-WTe2 (t)/Ni80Fe20/MgO/Ti （Td-WTN-t）异质结构中厚度相关的非常规面外τDL。对Td-WTN-12结构进行角分辨自旋-转矩铁磁共振测量，结果表明，该结构的自旋霍尔电导率为σSH，y = 4.93 × 103 （h /2e） Ω-1m-1, σSH,z = 0.81 × 103 （h /2e） Ω-1m-1，具有较好的自旋-轨道转矩器件应用前景。此外，对多晶少层Td-WTe2薄膜的磁输运特性作为厚度函数的详细研究表明，面外磁电阻明显放大，这可归因于材料内载流子散射机制的各向异性。在Td-WTN-t异质结构中的自旋泵浦测量进一步揭示了Td-WTe2的厚度相关自旋输运特性，通过阻尼分析得出平面外自旋扩散长度为λSD≈14 nm。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nanomaterials NANOSCIENCE & NANOTECHNOLOGY-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

8.50

自引率

9.40%

发文量

3841

审稿时长

14.22 days

期刊介绍： Nanomaterials (ISSN 2076-4991) is an international and interdisciplinary scholarly open access journal. It publishes reviews, regular research papers, communications, and short notes that are relevant to any field of study that involves nanomaterials, with respect to their science and application. Thus, theoretical and experimental articles will be accepted, along with articles that deal with the synthesis and use of nanomaterials. Articles that synthesize information from multiple fields, and which place discoveries within a broader context, will be preferred. There is no restriction on the length of the papers. Our aim is to encourage scientists to publish their experimental and theoretical research in as much detail as possible. Full experimental or methodical details, or both, must be provided for research articles. Computed data or files regarding the full details of the experimental procedure, if unable to be published in a normal way, can be deposited as supplementary material. Nanomaterials is dedicated to a high scientific standard. All manuscripts undergo a rigorous reviewing process and decisions are based on the recommendations of independent reviewers.