SrVO3薄膜中的轨道角动量积累
Orbital angular momentum accumulation in SrVO3 thin films
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中文总结 AI 辅助
本研究在SrVO3薄膜中观测到与轨道Hanle磁电阻一致的磁电阻特征，结合DFT计算和扩散模型估计，表明窄带d1金属氧化物是轨道输运的有前景平台。
中文摘要 AI 辅助
轻过渡金属中的轨道输运已成为角动量电子学的一条有前景的途径，其中Hanle磁电阻（HMR）为非磁性导体中的轨道霍尔效应（OHE）提供了直接的电子探针。本文报道了在(001)取向的(LaAlO3)0.3(Sr2TaAlO6)0.7衬底上生长的窄带d1氧化物外延SrVO3（SVO）中与轨道HMR一致的磁电阻特征。在不同厚度和纵向电阻率的薄膜中，场相关测量揭示了可重复的正、偶场且近似二次方的Δρx-y响应，这与HMR的预期一致。角度测量表征了相应的磁电阻各向异性，并揭示了额外的非Hanle贡献。密度泛函理论（DFT）计算得出费米能级处的本征轨道霍尔电导率σOH^DFT = 390 (ℏ/e) Ω^-1 cm^-1和自旋霍尔电导率σSH^DFT = -12 (ℏ/e) Ω^-1 cm^-1，对应|σOH^DFT/σSH^DFT| ≈ 33，表明以轨道响应为主。使用λOD = 2 nm作为参考值的扩散HMR框架，20.8 nm薄膜给出了保守的饱和极限下界（LB）估计θOH,LB = 0.0144 ± 0.0004和σOH,LB = (460 ± 11) (ℏ/e) Ω^-1 cm^-1，与DFT值相当。在整个系列中，使用相同λOD获得的下界估计总体上随纵向电导率的增加而增加。这些结果表明，窄带d1金属氧化物是轨道输运的一个有前景的平台。
英文摘要
Orbital transport in light transition metals has emerged as a promising route toward angular-momentum electronics, with Hanle magnetoresistance (HMR) providing a direct electrical probe of the orbital Hall effect (OHE) in non-magnetic conductors. Here we report magnetoresistance signatures consistent with orbital HMR in epitaxial SrVO$*3$ (SVO), a narrow-band $d^1$ oxide grown on (001)-oriented (LaAlO$*3$)$*{0.3}$(Sr$*2$TaAlO$*6$)$*{0.7}$ substrates. In films of different thickness and longitudinal resistivity, field-dependent measurements reveal a reproducible positive, even-in-field, and approximately quadratic $Δρ*{x-y}$ response, as expected for HMR. Angular measurements characterize the corresponding magnetoresistance anisotropy and reveal an additional non-Hanle contribution. Density functional theory (DFT) calculations yield an intrinsic orbital Hall conductivity $σ*{\mathrm{OH}}^{\mathrm{DFT}} = 390,(\hbar/e),Ω^{-1}\mathrm{cm}^{-1}$ and a spin Hall conductivity $σ_{\mathrm{SH}}^{\mathrm{DFT}} = -12,(\hbar/e),Ω^{-1}\mathrm{cm}^{-1}$ at the Fermi level, corresponding to $|σ_{\mathrm{OH}}^{\mathrm{DFT}}/σ_{\mathrm{SH}}^{\mathrm{DFT}}| \approx 33$, thus indicating a predominantly orbital response. Using the diffusive HMR framework with $λ_{\mathrm{OD}} = 2$ nm as a reference value, the 20.8 nm film gives conservative saturation-limit lower-bound (LB) estimates $θ_{\mathrm{OH,LB}} = 0.0144 \pm 0.0004$ and $σ_{\mathrm{OH,LB}} = (460 \pm 11),(\hbar/e),Ω^{-1}\mathrm{cm}^{-1}$, comparable to the DFT value. Across the series, lower-bound estimates obtained with the same $λ_{\mathrm{OD}}$ increase overall with longitudinal conductivity. These results suggest that narrow-band $d^1$ metallic oxides are a promising platform for orbital transport.
发表机构
- CIC nanoGUNE BRTA（巴斯克纳米材料中心）
- Department of Physics, Korea University（韩国大学物理系）
- Center for Quantum Dynamics of Angular Momentum（角动量量子动力学中心）
- Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC)（巴塞罗那材料科学研究所）
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