Stimulation with ultrafast light pulses can realize and manipulate states of matter with emergent structural, electronic and magnetic phenomena. However, these non-equilibrium phases are often transient and the challenge is to stabilize them as persistent states. Here, we show that atomic-scale PbTiO₃/SrTiO₃ superlattices, counterpoising strain and polarization states in alternate layers, are converted by sub-picosecond optical pulses to a supercrystal phase. This phase persists indefinitely under ambient conditions, has not been created via equilibrium routes, and can be erased by heating. X-ray scattering and microscopy show this unusual phase consists of a coherent three-dimensional structure with polar, strain and charge-ordering periodicities of up to 30 nm. By adjusting only dielectric properties, the phase-field model describes this emergent phase as a photo-induced charge-stabilized supercrystal formed from a two-phase equilibrium state. Our results demonstrate opportunities for light-activated pathways to thermally inaccessible and emergent metastable states.

超快光脉冲的刺激可以实现并操纵具有新兴结构，电子和磁性现象的物质状态。但是，这些非平衡阶段通常是瞬态的，而面临的挑战是将它们稳定成持久状态。在这里，我们显示了原子级的PbTiO ₃ / SrTiO ₃亚皮秒光脉冲将交替层中的超晶格，反平衡应变和极化状态转换为超晶相。此阶段在环境条件下无限期存在，尚未通过平衡途径建立，可以通过加热消除。X射线散射和显微镜显示该异常相由相干的三维结构组成，其极性，应变和电荷排序周期最高达30 nm。通过仅调整介电特性，相场模型将该新兴相描述为由两相平衡态形成的光感应电荷稳定超晶。我们的结果证明了光激活途径到达热不可及和出现的亚稳态的机会。