Multi-mode excitation drives disorder during the ultrafast melting of a C4-symmetry-broken phase.
Multi-mode excitation drives disorder during the ultrafast melting of a C4-symmetry-broken phase.
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DOI：
10.1038/s41467-021-27819-y
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发表时间：
2022-01-11
影响因子：
16.6
通讯作者：
Wall S
中科院分区：
文献类型：
--
作者：
Perez-Salinas D;Johnson AS;Prabhakaran D;Wall S
自发的C4对称性破缺相在层状量子材料中普遍存在，并且经常与其他相如超导性竞争。光对对称性破缺相的优先抑制已被用来解释非平衡光致超导、金属性和亚稳态的产生。理解这些阶段如何出现的关键是理解C4对称性如何恢复。一个领先的方法是基于时间相关的金兹伯格-朗道理论，它解释了在许多系统中看到的相干响应。然而，我们发现，对于单层锰氧化物La0.5Sr1.5MnO4的情况下，理论失败。相反，我们发现了一个超快的非均匀无序转变，其中平均场序参量不再反映系统的原子尺度状态。我们的研究结果表明，无序可能是共同的光诱导相变，和方法超越平均场是必要的理解和操纵光诱导相位。光致相变通常由含时平均场理论描述。在这里，作者表明，这样的理论未能捕捉到有序参数动力学在一个单一的层状锰氧化物和讨论的超快相变中的无序的作用一般。
Spontaneous C4-symmetry breaking phases are ubiquitous in layered quantum materials, and often compete with other phases such as superconductivity. Preferential suppression of the symmetry broken phases by light has been used to explain non-equilibrium light induced superconductivity, metallicity, and the creation of metastable states. Key to understanding how these phases emerge is understanding how C4 symmetry is restored. A leading approach is based on time-dependent Ginzburg-Landau theory, which explains the coherence response seen in many systems. However, we show that, for the case of the single layered manganite La0.5Sr1.5MnO4, the theory fails. Instead, we find an ultrafast inhomogeneous disordering transition in which the mean-field order parameter no longer reflects the atomic-scale state of the system. Our results suggest that disorder may be common to light-induced phase transitions, and methods beyond the mean-field are necessary for understanding and manipulating photoinduced phases. Light-induced phase transitions are typically described by a time-dependent mean-field theory. Here, the authors show that such a theory fails to capture the order parameter dynamics in a single layered manganite and discuss the role of disorder in ultrafast phase transitions in general.
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影响因子：
16.6
作者：
Miller, Timothy A.;Chhajlany, Ravindra W.;Wall, Simon
通讯作者：
Wall, Simon
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