发表机构
Universität Stuttgart; Max-Planck-Institut für Chemische Physik fester Stoffe; Goethe-Universität Frankfurt; Center for Correlated Matter and School of Physics, Zhejiang University（斯图加特大学; 马克斯·普朗克固体化学物理研究所; 法兰克福歌德大学; 浙江大学关联物质中心与物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究开发了极低温宽场宽频ESR观测方法，在YbRh2Si2的三个相区观测到ESR的g因子和线宽的不同行为，为量子临界性研究提供了实验依据。
AI 中文摘要
在重费米子金属YbRh2Si2中，受抑反铁磁序处的量子临界性由局域磁矩与巡游传导电子的相互作用主导。我们展示了如何通过一种新实验方法研究这一问题，该方法可在极低温下于宽频率和宽磁场范围内观测电子自旋共振（ESR）。这使我们能覆盖从顺磁费米液体相到反铁磁序相、包含量子临界区的相图大部分区域。ESR的g因子和线宽在这三个区域呈现不同行为，为理解量子临界点附近的物理提供了进一步见解。值得注意的是，当在磁场下直接冷却至量子临界点时，g因子和线宽均持续减小。此外，我们观测到在向量子临界点进行磁场调谐和温度调谐时，g因子的行为匹配度极高。我们在强关联电子系统ESR的现有理论框架下分析并讨论了这些结果。
英文摘要
In the heavy-fermion metal YbRh2Si2, quantum criticality at a suppressed antiferromagnetic order is governed by the interplay of local magnetic moments and itinerant conduction electrons. We demonstrate how this can be investigated by a new experimental approach that enables the observation of electron spin resonance (ESR) across a broad range of frequencies and fields at very low temperatures. This allowed us to cover a large part of the phase diagram from the paramagnetic Fermi-liquid phase to the phase with antiferromagnetic order and including the quantum-critical regime. Both the ESR g-factor and the linewidth present distinct behaviors in these three regimes, providing further insight into the physics across a quantum critical point. Notably, when cooling down at a field directly towards the quantum critical point, both g-factor and linewidth continuously decrease. Furthermore, we observe a very good matching of the g-factor behavior upon field-tuning and temperature-tuning towards the quantum-critical point. We analyze and discuss the results in the context of present theories on ESR in strongly correlated electron systems.
CommentsPhysical Review Letters, Editors Suggestion, 7 pages, 9 pages Supplementary Material, 4+7 figures
Journal refPhys. Rev. Lett. 137, 136506 (2026)
