论文标题
在CSPBI3 perovskite量子点中诱导激子分裂和连贯的量子跳动的晶格失真
Lattice distortion inducing exciton splitting and coherent quantum beating in CsPbI3 perovskite quantum dots
论文作者
论文摘要
半导体量子点（QDS）中各向异性交换分解会导致明亮的优质结构分解（FSS）对于量子信息处理至关重要。 FSS的直接测量通常需要在液晶温度下进行单个/几个QD，因为它对QD的尺寸和形状的敏感性，而在集合级别的测量和控制FSS似乎是不可能的，除非所有点都使所有点几乎相同。在这里，我们报告了在溶液处理的CSPBI3钙钛矿QD中，强烈的亮点FSS高达1.6 MeV，在液体氮气中的集合级瞬时吸收中，表现为量子节拍。分裂对QD尺寸和形状异质性是可靠的，并且随温度降低而增加，指向与钙钛矿晶格的正交畸变相关的机制。有效的质量 - 及时计算揭示了一个内在的“细构造差距”，与观察到的FSS非常吻合。这一差距源于避免在正骨延伸的QD中的明亮脱口酸的穿越，这些QD受伪观察{100}平面家族的界定。
Anisotropic exchange-splitting in semiconductor quantum dots (QDs) results in bright-exciton fine-structure-splitting (FSS) important for quantum information processing. Direct measurement of FSS usually requires single/few QDs at liquid-helium temperatures, because of its sensitivity to QD size and shape, whereas measuring and controlling FSS at an ensemble-level seem to be impossible unless all the dots are made to be nearly the same. Here we report strong bright-exciton FSS up to 1.6 meV in solution-processed CsPbI3 perovskite QDs, manifested as quantum beats in ensemble-level transient absorption at liquid-nitrogen to room temperatures. The splitting is robust to QD size and shape heterogeneity, and increases with decreasing temperature, pointing towards a mechanism associated with orthorhombic distortion of perovskite lattice. Effective-mass-approximation calculations reveal an intrinsic "fine-structure gap" that agrees well with the observed FSS. This gap stems from an avoided crossing of bright-excitons confined in orthorhombically-distorted QDs that are bounded by the pseudocubic {100} family of planes.
