Sim Kyung Ik, Kim Jae Hoon, Park Byung Cheol
Sungkyunkwan University, Suwon, Republic of Korea.
Center for Integrated Nanostructure Physics, Sungkyunkwan University, Suwon, Republic of Korea.
Nat Commun. 2025 Mar 11;16(1):2444. doi: 10.1038/s41467-025-57777-8.
Light-matter interaction simultaneously alters both the original material and incident light. Light not only reveals material details but also activates coupling mechanisms. The coupling has been demonstrated mechanically, for instance, through the patterning of metallic antennas, resulting in the emergence of plasmonic quasiparticles and enabling wavefront engineering of light via the generalized Snell's law. However, quantum-mechanical light-matter interaction, wherein photons coherently excite distinct quantum pathways, remains poorly understood. Here, we report on quantum interference between light-induced quantum pathways through the orbital quantum levels and spin continuum. The quantum interference immediately breaks the symmetry of the hexagonal antiferromagnetic semiconductor FePS. Below the Néel temperature, we observe the emergence of birefringence and linear dichroism, namely, quantum anisotropy due to quantum interference, which is further enhanced by the thickness effect. We explain the direct relevance of the quantum anisotropy to a quantum phase transition by spontaneous symmetry breaking in Mexican hat potential. Our findings suggest material modulation via selective quantum pathways through quantum light-matter interaction.
光与物质的相互作用同时改变了原始材料和入射光。光不仅揭示了材料细节，还激活了耦合机制。例如，通过金属天线的图案化，已经在机械上证明了这种耦合，从而导致了等离子体准粒子的出现，并通过广义斯涅尔定律实现了光的波前工程。然而，量子力学的光与物质相互作用，即光子相干地激发不同的量子路径，仍然知之甚少。在这里，我们报告了通过轨道量子能级和自旋连续体在光诱导量子路径之间的量子干涉。这种量子干涉立即打破了六角反铁磁半导体FePS的对称性。在奈尔温度以下，我们观察到双折射和线性二色性的出现，即由于量子干涉导致的量子各向异性，其通过厚度效应进一步增强。我们通过墨西哥帽势中的自发对称性破缺来解释量子各向异性与量子相变的直接相关性。我们的发现表明，通过量子光与物质相互作用的选择性量子路径可以实现材料调制。
