近日，法国巴黎萨克雷大学的Michel Viret及其研究小组取得一项新进展。经过不懈努力，他们成功观察到了轨道反演Rashba-Edelstein效应。相关研究成果已于2023年7月10日在国际知名学术期刊《自然—物理学》上发表。
该研究团队在LaAlO3/SrTiO3界面上观察到了自旋-电荷转换现象，并证明了轨道贡献在其中起主导作用。研究人员通过对面内各向异性和栅极电压依赖性的角动量转化为电荷的分析，突出了轨道Rashba分裂的一些显著特征。这些结果揭示了纯轨道角动量效应的潜力，并证实了轨道自由度在信息存储和处理方面的重要性。这为进一步利用纯轨道角动量效应打开了新的可能性。
据悉，自旋轨道相互作用在磁学和许多量子材料中扮演着重要角色。它是许多电子相在界面上出现的物理基础，因为反演对称性被破坏。在这种情况下，自旋Rashba效应将具有动量的电子自旋锁定，从而导致显著的自旋电流效应。最近的研究表明，这些基于自旋的效应实际上可能是自旋-轨道耦合的结果，而轨道效应可能具有更广泛的影响。这一发现揭示了自旋轨道相互作用的潜在机制和重要性。
附：英文原文
Title: Observation of the orbital inverse Rashba–Edelstein effect
Author: El Hamdi, Anas, Chauleau, Jean-Yves, Boselli, Margherita, Thibault, Clmentine, Gorini, Cosimo, Smogunov, Alexander, Barreteau, Cyrille, Gariglio, Stefano, Triscone, Jean-Marc, Viret, Michel
Issue&Volume: 2023-07-10
Abstract: The spin–orbit interaction plays an important role in magnetism and in many quantum materials. It is the cornerstone of the physics of many electronic phases that emerge at interfaces because of broken inversion symmetry. In that context, the spin Rashba effect locks electronic spins with momentum to produce large spin galvanic effects. It has recently been argued that these spin-based effects could in fact be spin–orbit coupling consequences of a potentially larger orbital effect. Here we observe spin-to-charge conversion at a LaAlO3/SrTiO3 interface and demonstrate that its orbital contribution dominates. Our analysis of the in-plane anisotropy and gate voltage dependence of the angular momentum conversion into charge highlights some of the salient features of the orbital Rashba splitting. These results open the door to broader use of pure orbital angular momentum effects and confirm the potential of the orbital degree of freedom for information storage and processing.
DOI: 10.1038/s41567-023-02121-4
Source: https://www.nature.com/articles/s41567-023-02121-4