近日，英国圣安德鲁斯大学的Peter Wahl及其研究小组取得一项新进展。经过不懈努力，他们揭示了Sr₃Ru₂O₇中电子向列性的类指南针操纵。相关研究成果已于2023年8月28日在国际知名学术期刊《美国科学院院刊》上发表。

该研究团队报道了Sr₃Ru₂O₇表面电子结构的场控制各向异性的光谱成像。研究人员跟踪了电子结构作为场方向的函数，揭示了随角度的连续变化。这种持续的演化表明了一种基于自旋-轨道耦合的机制，导致了电子能带的类似指南针的控制。电子结构的各向异性持续到温度比主体高一个数量级，这展示了在更宽的温度范围内稳定这些相的新途径。

据悉，在广泛的强关联电子材料中发现了电子向列性，这导致电子态的对称性低于容纳它们的晶体的对称性。最令人惊讶的例子之一是Sr₃Ru₂O₇，其中一个小的面内磁场分量会引起显著的电阻率各向异性。这种各向异性的方向遵循平面内场的方向。这种场致向列性的微观起源一直是一个长期存在的谜题，最近的实验表明，场致自旋密度波驱动了各向异性。

附：英文原文

Title: Compass-like manipulation of electronic nematicity in Sr₃Ru₂O₇

Author: Naritsuka, Masahiro, Benedii, Izidor, Rhodes, Luke C., Marques, Carolina A., Trainer, Christopher, Li, Zhiwei, Komarek, Alexander C., Wahl, Peter

Issue&Volume: 2023-8-28

Abstract: Electronic nematicity has been found in a wide range of strongly correlated electron materials, resulting in the electronic states having a symmetry that is lower than that of the crystal that hosts them. One of the most astonishing examples is Sr₃Ru₂O₇, in which a small in-plane component of a magnetic field induces significant resistivity anisotropy. The direction of this anisotropy follows the direction of the in-plane field. The microscopic origin of this field-induced nematicity has been a long-standing puzzle, with recent experiments suggesting a field-induced spin density wave driving the anisotropy. Here, we report spectroscopic imaging of a field-controlled anisotropy of the electronic structure at the surface of Sr₃Ru₂O₇. We track the electronic structure as a function of the direction of the field, revealing a continuous change with the angle. This continuous evolution suggests a mechanism based on spin–orbit coupling resulting in compass-like control of the electronic bands. The anisotropy of the electronic structure persists to temperatures about an order of magnitude higher compared to the bulk, demonstrating novel routes to stabilize such phases over a wider temperature range.

DOI: 10.1073/pnas.2308972120

Source: https://www.pnas.org/doi/10.1073/pnas.2308972120