Portnichenko P Y, Romhányi J, Onykiienko Y A, Henschel A, Schmidt M, Cameron A S, Surmach M A, Lim J A, Park J T, Schneidewind A, Abernathy D L, Rosner H, van den Brink Jeroen, Inosov D S
Institut für Festkörperphysik, TU Dresden, Helmholtzstraße 10, D-01069 Dresden, Germany.
Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany.
Nat Commun. 2016 Feb 25;7:10725. doi: 10.1038/ncomms10725.
Complex low-temperature-ordered states in chiral magnets are typically governed by a competition between multiple magnetic interactions. The chiral-lattice multiferroic Cu2OSeO3 became the first insulating helimagnetic material in which a long-range order of topologically stable spin vortices known as skyrmions was established. Here we employ state-of-the-art inelastic neutron scattering to comprehend the full three-dimensional spin-excitation spectrum of Cu2OSeO3 over a broad range of energies. Distinct types of high- and low-energy dispersive magnon modes separated by an extensive energy gap are observed in excellent agreement with the previously suggested microscopic theory based on a model of entangled Cu4 tetrahedra. The comparison of our neutron spectroscopy data with model spin-dynamical calculations based on these theoretical proposals enables an accurate quantitative verification of the fundamental magnetic interactions in Cu2OSeO3 that are essential for understanding its abundant low-temperature magnetically ordered phases.
手性磁体中的复杂低温有序态通常由多种磁相互作用之间的竞争所支配。手性晶格多铁性材料Cu2OSeO3成为了第一种绝缘螺旋磁体材料，其中建立了一种被称为斯格明子的拓扑稳定自旋涡旋的长程有序态。在此，我们采用最先进的非弹性中子散射技术，以全面了解Cu2OSeO3在广泛能量范围内的三维自旋激发光谱。我们观察到由一个宽能隙分隔的不同类型的高能和低能色散磁振子模式，这与之前基于纠缠Cu4四面体模型提出的微观理论非常吻合。将我们的中子光谱数据与基于这些理论提议的模型自旋动力学计算进行比较，能够对Cu2OSeO3中基本磁相互作用进行精确的定量验证，而这些相互作用对于理解其丰富的低温磁有序相至关重要。
