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arXiv 0901.3287cond-mat.mes-hallcond-mat.mtrl-sci
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Pd和Au本征自旋霍尔电导的从头计算

Ab initio calculation of intrinsic spin Hall conductivity of Pd and Au

G. Y. Guo

摘要:

本文用相对论方法计算了Pd和Au金属自旋霍尔电导(SHC)($σ_{xy}^z$)的{ \it ab initio}能带结构.发现在低温下,Pd和Au的本征自相似性分别为$\sim 1400 (\hbar/e)(Ω{\rm cm})^{-1}$和$\sim 400 (\hbar/e)(Ω{\rm cm})^{-1}$ . Pd中较大的自洽场来自于费米能级附近对称点$Γ$和X点处双简并的4个$d$带的自旋-轨道分裂的共振贡献,Au中较小的自洽场是由于类似6个$s6p$ -带的宽自由电子。然而,随着温度的升高,Pd中的SHC单调降低,在300 K时降低到$\sim 330 (\hbar/e)(Ω{\rm cm})^{-1}$,而Au中的SHC稳定增加,在室温时达到$\sim 750 (\hbar/e)(Ω{\rm cm})^{-1}$。这表明最近在Au/FePt体系中观察到的巨自旋霍尔效应[ $σ_{xy}^z \approx 10^5 (\hbar/e)(Ω{\rm cm})^{-1}$ ][T. Seki,{ \it等},Nature Materials { \bf 7},125(2008)]是由于诸如Au中杂质的斜散射的外在机制。

英文摘要:

An {\it ab initio} relativistic band structure calculation of spin Hall conductivity (SHC) ($σ_{xy}^z$) in Pd and Au metals has been performed. It is found that at low temperatures, intrinsic SHCs for Pd and Au are, respectively, $\sim 1400 (\hbar/e)(Ω{\rm cm})^{-1}$ and $\sim 400 (\hbar/e)(Ω{\rm cm})^{-1}$. The large SHC in Pd comes from the resonant contribution from the spin-orbit splitting of the doubly degenerated 4$d$ bands near the Fermi level at symmetry $Γ$ and X points, and the smaller SHC in Au is due to the broad free electron like 6$s6p$-bands. However, as the temperature increases, the SHC in Pd decreases monotonically and reduces to $\sim 330 (\hbar/e)(Ω{\rm cm})^{-1}$ at 300 K, while the SHC in Au increases steadily and reaches $\sim 750 (\hbar/e)(Ω{\rm cm})^{-1}$ at room temperature. This indicates that the gigantic spin Hall effect [$σ_{xy}^z \approx 10^5 (\hbar/e)(Ω{\rm cm})^{-1}$] observed recently in the Au/FePt system [T. Seki, {\it et al.}, Nature Materials {\bf 7}, 125 (2008)] is due to the extrinsic mechanisms such as the skew scattering by the impurities in Au.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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