Optical creation of a supercrystal with three-dimensional nanoscale periodicity
Optical creation of a supercrystal with three-dimensional nanoscale periodicity
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DOI：
10.1038/s41563-019-0311-x
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发表时间：
2019-04-01
期刊：
影响因子：
41.2
通讯作者：
Freeland, J. W.
中科院分区：
文献类型：
--
作者：
Stoica, V. A.;Laanait, N.;Freeland, J. W.
利用超快光脉冲的激发可以实现和操纵具有出射结构、电子和磁现象的物质状态。然而，这些非平衡相通常是短暂的，挑战是将它们稳定为持久状态。在这里，我们表明，原子级的PbTiO 3/SrTiO 3超晶格，抵消应变和偏振态的交替层，由亚皮秒光脉冲转换成超晶相。该相在环境条件下无限期地存在，没有通过平衡途径产生，并且可以通过加热消除。X射线散射和显微镜显示，这个不寻常的阶段包括一个连贯的三维结构与极性，应变和电荷有序周期高达30 nm。通过调整介电性质，相场模型描述了这个新兴的阶段作为一个光诱导的电荷稳定的超晶体形成的两相平衡状态。我们的研究结果表明，光激活途径的热不可及和紧急亚稳态的机会。
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.