超越单磁振子和双磁振子的磁激发。

Magnetic excitations beyond the single- and double-magnons.

机构信息

Debye Institute for Nanomaterials Science, Utrecht University, 3584 CA, Utrecht, The Netherlands.

Institute of Mineralogy, Physics of Materials and Cosmochemistry, CNRS, Sorbonne University, 4 Place Jussieu, 75005, Paris, France.

出版信息

Nat Commun. 2023 May 12;14(1):2749. doi: 10.1038/s41467-023-38341-8.

DOI:10.1038/s41467-023-38341-8

PMID:37173301

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10182046/

Abstract

A photon carrying one unit of angular momentum can change the spin angular momentum of a magnetic system with one unit (ΔM = ±1) at most. This implies that a two-photon scattering process can manipulate the spin angular momentum of the magnetic system with a maximum of two units. Herein we describe a triple-magnon excitation in α-FeO, which contradicts this conventional wisdom that only 1- and 2-magnon excitations are possible in a resonant inelastic X-ray scattering experiment. We observe an excitation at exactly three times the magnon energy, along with additional excitations at four and five times the magnon energy, suggesting quadruple and quintuple-magnons as well. Guided by theoretical calculations, we reveal how a two-photon scattering process can create exotic higher-rank magnons and the relevance of these quasiparticles for magnon-based applications.

摘要

一个携带一个角动量单位的光子最多只能使磁系统的自旋角动量改变一个单位（ΔM = ±1）。这意味着双光子散射过程最多可以用两个单位来操纵磁系统的自旋角动量。在此，我们描述了在 α-FeO 中三重磁激元激发，这与传统观点相矛盾，传统观点认为在共振非弹性 X 射线散射实验中只能存在 1 磁元和 2 磁元激发。我们观察到一个正好是磁元能量三倍的激发，还有四倍和五倍磁元能量的额外激发，表明存在四重和五重磁元激发。在理论计算的指导下，我们揭示了双光子散射过程如何产生奇异的更高阶磁元激发，以及这些准粒子在基于磁元的应用中的相关性。