Coupling microwave photons to topological spin textures in Cu2OSeO3
Coupling microwave photons to topological spin textures in Cu2OSeO3
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DOI：
10.1103/physrevb.104.l100402
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发表时间：
2021-09-03
影响因子：
3.7
通讯作者：
Kurebayashi, H.
中科院分区：
文献类型：
--
作者：
Khan, S.;Lee, O.;Kurebayashi, H.
受拓扑保护的纳米级自旋织构，即所谓的磁性Skyrmions，具有粒子性质和突现的磁效应。在块状立方日冕中，已经使用自旋电子学中的铁磁共振等技术识别出了不同的天米子共振模。然而，微波光子和天米子共振模之间的直接光-物质耦合仍然需要证明。利用两个不同的腔系统，我们观察到块状Cu2OSeO_3中腔谐振模与两个共振Skyrmion模--逆时针旋转模和呼吸模之间的直接相互作用。对于这两种共振模式，我们发现在57K时耦合强度最大，表现为简并点的腔线宽增大。我们研究了在预期的Skyrmion相范围内有效耦合强度随温度的变化。我们将有效耦合强度的最大值归因于大量Skyrmion的存在，并相应地归因于完全稳定的Skyrmion晶格。我们的实验结果表明，光子与磁性天子谐振模之间的耦合依赖于这些拓扑粒子的相对密度，而不是系统中的纯自旋数。
Topologically protected nanoscale spin textures, known as magnetic skyrmions, possess particlelike properties and feature emergent magnetism effects. In bulk cubic helimagnets, distinct skyrmion resonant modes are already identified using a technique such as ferromagnetic resonance in spintronics. However, direct light-matter coupling between microwave photons and skyrmion resonance modes still needs to be demonstrated. Utilizing two distinct cavity systems, we observe a direct interaction between the cavity resonant mode and two resonant skyrmion modes, the counterclockwise gyration and breathing modes, in bulk Cu2OSeO3. For both resonant modes, we find the largest coupling strength at 57 K indicated by an enhancement of the cavity linewidth at the degeneracy point. We study the effective coupling strength as a function of temperature within the expected skyrmion phase. We attribute the maximum in effective coupling strength to the presence of a large number of skyrmions, and correspondingly to a completely stable skyrmion lattice. Our experimental findings indicate that the coupling between photons and resonant modes of magnetic skyrmions depends on the relative density of these topological particles instead of the pure spin number in the system.