Enhanced robustness and dimensional crossover of superradiance in cuboidal nanocrystal superlattices
Enhanced robustness and dimensional crossover of superradiance in cuboidal nanocrystal superlattices
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DOI：
10.1103/physrevresearch.5.023068
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发表时间：
2022-09
影响因子：
4.2
通讯作者：
Sushrut Ghonge;David Engel;F. Mattiotti;G. Celardo;M. Kuno;B. Jank'o
中科院分区：
文献类型：
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作者：
Sushrut Ghonge;David Engel;F. Mattiotti;G. Celardo;M. Kuno;B. Jank'o
在各种物理系统中，已经预测和观察到了多个发射体的相干辐射的协同辐射(称为超辐射)，最近的一次是在CsPbBr3$纳米晶体超晶格中。超辐射发射是相干的，发生在时间尺度上的速度比孤立纳米晶体的发射快。理论预测，合作发射的速度最高可达纳米晶体数量的1倍(N美元)。然而，由于纳米晶体尺寸变化和热退相干引起的能量无序的存在，超辐射被强烈地抑制。在这里，我们分析了具有不同纳米晶体长宽比的不同维度(一维、二维和三维)的超晶格的超辐射。我们预测，在由立方体形状的纳米晶体组成的三维(3D)超晶格中，相对于能量无序的现实值，稳健性将提高多达15倍。由小的$(N\less sim 10^3)$二维(2D)超晶格产生的超辐射对静态无序的健壮性是相同$N的3D超晶格的10倍，对热退相干的健壮性是3D超晶格的两倍。随着$N$数目的增加，超辐射的稳健性从2D超晶格向3D超晶格发生交叉。对于大的$N\(>；10^3)$，三维超晶格的稳健性随着$N的增加而增加，表现出对无序的合作稳健性。如果纳米晶体的尺寸波动能够保持很小，这就开启了即使在室温下也能在大型3D超晶格中观察到超辐射的可能性。
Cooperative emission of coherent radiation from multiple emitters (known as superradiance) has been predicted and observed in various physical systems, most recently in CsPbBr$_3$ nanocrystal superlattices. Superradiant emission is coherent and occurs on timescales faster than the emission from isolated nanocrystals. Theory predicts cooperative emission being faster by a factor of up to the number of nanocrystals ($N$). However, superradiance is strongly suppressed due to the presence of energetic disorder, stemming from nanocrystal size variations and thermal decoherence. Here, we analyze superradiance from superlattices of different dimensionalities (one-, two- and three-dimensional) with variable nanocrystal aspect ratios. We predict as much as a 15-fold enhancement in robustness against realistic values of energetic disorder in three-dimensional (3D) superlattices composed of cuboid-shaped, as opposed to cube-shaped, nanocrystals. Superradiance from small $(N\lesssim 10^3)$ two-dimensional (2D) superlattices is up to ten times more robust to static disorder and up to twice as robust to thermal decoherence than 3D superlattices with the same $N$. As the number of $N$ increases, a crossover in the robustness of superradiance occurs from 2D to 3D superlattices. For large $N\ (>10^3)$, the robustness in 3D superlattices increases with $N$, showing cooperative robustness to disorder. This opens the possibility of observing superradiance even at room temperature in large 3D superlattices, if nanocrystal size fluctuations can be kept small.