Tuneable electron-magnon coupling of ferromagnetic surface states in PdCoO2
Tuneable electron-magnon coupling of ferromagnetic surface states in PdCoO2
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DOI：
10.1038/s41535-022-00428-8
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发表时间：
2022-02-11
影响因子：
5.7
通讯作者：
King, P. D. C.
中科院分区：
文献类型：
--
作者：
Mazzola, F.;Yim, C-M;King, P. D. C.
控制磁性材料中的自旋波激发是新兴的磁学领域的基础。然而，对于磁振子如何与流动磁体的传导电子相互作用，以及如何控制这种相互作用，人们知之甚少。通过表面敏感光谱方法，我们证明了delafoite氧化物PdCoO2的pd端表面存在强电子-磁振子耦合，其中极性表面电荷介导了斯通纳向流动表面铁磁性的转变。我们展示了耦合如何随着表面无序性的增加和伴随的载流子掺杂而增强七倍，变得足够强以驱动系统进入极化状态，伴随着显著的准粒子质量增强。因此，我们的研究揭示了固态材料中的电子-磁振子相互作用，以及控制这些相互作用的方法。
Controlling spin wave excitations in magnetic materials underpins the burgeoning field of magnonics. Yet, little is known about how magnons interact with the conduction electrons of itinerant magnets, or how this interplay can be controlled. Via a surface-sensitive spectroscopic approach, we demonstrate a strong electron-magnon coupling at the Pd-terminated surface of the delafossite oxide PdCoO2, where a polar surface charge mediates a Stoner transition to itinerant surface ferromagnetism. We show how the coupling is enhanced sevenfold with increasing surface disorder, and concomitant charge carrier doping, becoming sufficiently strong to drive the system into a polaronic regime, accompanied by a significant quasiparticle mass enhancement. Our study thus sheds light on electron-magnon interactions in solid-state materials, and the ways in which these can be controlled.