近日，美国斯坦福大学Felipe H. da Jornada团队报道了用激子场驱动弗洛凯物理学。这一研究成果于2026年1月19日发表在《自然—物理学》杂志上。

弗洛凯工程——通过强光场调控材料电子结构——为操控量子和拓扑性质提供了新途径。然而，由于光与物质耦合相对较弱，且多光子吸收、样品发热等不利效应往往占主导地位，实验实现该技术仍面临挑战。

研究组利用时间与角分辨光电子能谱技术证明：在单层半导体中，由激子场引发的弗洛凯效应（即电子与空穴结合形成的自能随时间周期性振荡）比光驱动效应强两个数量级，且持续时间更长。实验直接观测到二维半导体中激子修饰的导带与价带发生杂化现象，该结果与第一性原理计算相符。随着激子密度增加，这种杂化效应的出现与玻色-爱因斯坦凝聚-巴丁-库珀-施里弗交叉行为相关，该现象在非平衡激子绝缘体理论中被广泛讨论。该研究成果确立了激子驱动弗洛凯工程作为研究关联电子相态的重要手段。

附：英文原文

Title: Driving Floquet physics with excitonic fields

Author: Pareek, Vivek, Bacon, David R., Zhu, Xing, Chan, Yang-Hao, Bussolotti, Fabio, Menezes, Marcos G., Chan, Nicholas S., Urquizo, Joel Prez, Watanabe, Kenji, Taniguchi, Takashi, Perfetto, Enrico, Man, Michael K. L., Mado, Julien, Stefanucci, Gianluca, Qiu, Diana Y., Goh, Kuan Eng Johnson, da Jornada, Felipe H., Dani, Keshav M.

Issue&Volume: 2026-01-19

Abstract: Floquet engineering, in which an intense optical field modifies the electronic structure of a material, offers a route to the control of quantum and topological properties. However, it is challenging to realize this in experiments due to relatively weak light–matter coupling and the dominance of detrimental effects, such as multi-photon absorption and sample heating. Here we use time- and angle-resolved photoemission spectroscopy to show that in a monolayer semiconductor, Floquet effects caused by an excitonic field—the time-periodic oscillations of the self-energy of an electron bound to a hole—are two orders of magnitude stronger and persist longer than optically driven counterparts. Our measurements directly capture the hybridization between the exciton-dressed conduction band and the valence band in two-dimensional semiconductors, in agreement with first-principles calculations. The onset of this hybridization with increasing exciton density also correlates with the Bose–Einstein condensation to Bardeen–Cooper–Schrieffer crossover, extensively discussed in theory for non-equilibrium excitonic insulators. These results establish exciton-driven Floquet engineering as a means for studying correlated electronic phases.

DOI: 10.1038/s41567-025-03132-z

Source: https://www.nature.com/articles/s41567-025-03132-z