Schönfeld Christoph, Feuerer Lennart, Bär Julian, Dörfelt Lukas, Kerstingskötter Maik, Dannegger Tobias, Wuhrer Dennis, Belzig Wolfgang, Nowak Ulrich, Leitenstorfer Alfred, Juraschek Dominik, Bossini Davide
Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany.
School of Physics and Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel.
Sci Adv. 2025 Jun 20;11(25):eadv4207. doi: 10.1126/sciadv.adv4207.
Sustaining the growth of the data volume generated by artificial intelligence and the internet of things demands to develop schemes for data storage and processing operating at terahertz frequencies, unrestrained by thermal throttling. The optical drive of coherent magnetic collective excitations, namely magnons, represents a promising route. The ability to arbitrarily and nonthermally increase the magnon frequencies with laser pulses could enable this progress. However, this effect has not been reported to date. To achieve it, here, we explore the optical resonant excitation of high-momentum magnons, which experimentally are observed to couple to low-momentum magnons, modifying the frequencies and amplitudes thereof. This evidence, not caused by laser heating, is explained with a resonant light-scattering mechanism coupling high- and low-momentum eigenmodes across momentum space. Our results disclose routes to inducing instabilities and phase transitions via mode softening and potentially even light-driven Bose-Einstein condensation of magnons and superconductivity mediated by high-momentum spin-fluctuations.
维持人工智能和物联网产生的数据量增长需要开发在太赫兹频率下运行的数据存储和处理方案，不受热节流的限制。相干磁集体激发（即磁振子）的光驱动是一条很有前途的途径。用激光脉冲任意地、非热地增加磁振子频率的能力可以推动这一进展。然而，迄今为止尚未报道过这种效应。为了实现这一目标，我们在此探索高动量磁振子的光学共振激发，实验中观察到它与低动量磁振子耦合，从而改变其频率和振幅。这一并非由激光加热引起的证据，通过一种在动量空间中耦合高动量和低动量本征模的共振光散射机制来解释。我们的结果揭示了通过模式软化诱导不稳定性和相变的途径，甚至可能实现光驱动的磁振子玻色 - 爱因斯坦凝聚以及由高动量自旋涨落介导的超导性。
