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arXiv 2402.07533cond-mat.mes-hall
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通过扭转角调控石墨烯/NbSe$_2$异质结中的邻近自旋轨道耦合

Tuning proximity spin-orbit coupling in graphene/NbSe$_2$ heterostructures via twist angle

Thomas Naimer, Martin Gmitra, Jaroslav Fabian

AI总结:

本文通过第一性原理研究扭转角对石墨烯/NbSe$_2$异质结邻近自旋轨道耦合的影响,预测Rashba SOC强度可随扭转角增大至三倍,并揭示其轨道杂化机制及电荷-自旋转换效率。

摘要:

我们从第一性原理出发,研究了扭转角对石墨烯/NbSe$_2$异质结中邻近自旋轨道耦合(SOC)的影响。我们将若干不同公度扭转超胞的低能狄拉克能带拟合到一个模型哈密顿量上,从而能够详细研究SOC随扭转角的变化关系。我们预测,当扭转角从$Θ=0^\circ$变化到$Θ=30^\circ$时,Rashba SOC的强度可以增大至原来的三倍。此外,在$Θ\approx23^\circ$的扭转角下,面内自旋织构获得较大的径向分量,对应的Rashba角最高可达$Φ=25^\circ$。通过分析狄拉克态的轨道分解,揭示它们与哪些NbSe$_2$能带杂化最强,我们解释了所提取的邻近SOC对扭转角的依赖关系。最后,我们采用Kubo公式评估了所研究异质结中常规与非常规电荷-自旋转换的效率。

英文摘要:

We investigate the effect of the twist angle on the proximity spin-orbit coupling (SOC) in graphene/NbSe$_2$ heterostructures from first principles. The low-energy Dirac bands of several different commensurate twisted supercells are fitted to a model Hamiltonian, allowing us to study the twist-angle dependency of the SOC in detail. We predict that the magnitude of the Rashba SOC can triple, when going from $Θ=0^\circ$ to $Θ=30^\circ$ twist angle. Furthermore, at a twist angle of $Θ\approx23^\circ$ the in-plane spin texture acquires a large radial component, corresponding to a Rashba angle of up to $Φ=25^\circ$. The twist-angle dependence of the extracted proximity SOC is explained by analyzing the orbital decomposition of the Dirac states to reveal with which NbSe$_2$ bands they hybridize strongest. Finally, we employ a Kubo formula to evaluate the efficiency of conventional and unconventional charge-to-spin conversion in the studied heterostructures.

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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