Electron dynamics of ultrafast energytransfer processes among quantum dots induced by long range electron correlation

近几年来，原子团簇和分子团簇中由长程电子关联引起的超快能量转移过程成为理论界和实践界关注的焦点。第一次发现了原子间库仑衰变(ICD)过程，在ICD过程中，一个电子激发的分子阳离子弛豫到基态，而邻近分子被电离。从那时起，人们在经典的原子和分子系统中研究了ICD的许多变体。2011年，随着一本关于量子点(QD)中ICD过程的出版物，我开始对这些技术相关的半导体材料的前述能量转移过程进行研究。在这一新的方法中，根据有效质量近似(EMA)，在量子点的模型势中进行了高度关联的电子动力学计算，这也是本项目的基础。由于模型势的存在，所得结果对不同种类的量子点具有高度的通用性。此外，我还利用电子动力学对ICD等长距离能量传递过程进行了计算。为此，我使用了对高度相关的多组态时间相关Hartree-(MCTDH)方法的反对称修正，该方法提供了定义在包括连续体在内的完整组态空间中的波函数的详细知识。此外，它还允许自然地采用光脉冲和散射电子。因此，整个程序对于预测ICD和QD中的相关现象是最优的。在这个项目中，我试图扩展现有的方法组合，使其能够在实验上可行的各种量子点阵列中对电子和能量转移过程做出快速、灵活和有约束力的预测。为此，该模型将与声子和激子的动力学处理相结合，并进一步推广到各种实际的量子点几何形状。将测试用于光学控制能量传递过程的不同形式和强度的电场。量子点中相关电子的数量将连续增加，这需要从MCTDH过渡到更有效的电子动力学方法，假设是基于高斯的方法。在此基础上，为在现实的量子点阵列中，以及原子和分子中超快、远程电子和能量转移过程的一般电子动力学处理奠定了基础。预期结果将进一步推动技术上使用这些过程，即用于产生慢电子的原子间库仑电子俘获(ICEC)和用于红外光电探测器的ICD。

Since a couple of years ultrafast energy transfer processes in clusters of atoms and molecules mediated by long-range electron correlation came into the focus of theoreticians and experimentalists. As a first process of such kind the interatomic Coulombic decay (ICD) was discovered, in which an electronically excited molecular cation relaxes into its ground state, while a neighboring molecule is ionized. Since then many variants of ICD were investigated in classical atomic and molecular systems. With a publication on the ICD process in quantum dots (QDs) in 2011 I started to establish the research on the aforementioned energy transfer processes for these technologically relevant semiconductor materials. In the novel methodology, on which also this project is based, highly correlated electron dynamics calculations are performed in model potentials for QDs according to the effective mass approximation (EMA). Due to the model potentials the results have a high degree of generality for different sorts of QDs. I further distinguish myself by using electron dynamics for calculations on a long-distance energy transfer processes as ICD. To do so I use an antisymmetric modification of the highly correlated multi-configuration time-dependent Hartree- (MCTDH) method that offers detailed knowledge of the wave function defined in the complete configuration space including the continuum. It furthermore allows for the natural adoption of optical pulses and scattering electrons. Therefore the whole procedure is optimal for the prediction of ICD and related phenomena in QDs.In this project I seek to extend the existing portfolio of methods in such a way that it becomes possible to make quick, flexible and binding predictions on electron and energy transfer processes in experimentally feasible arrays of various kinds of QDs. For this purpose the model will be combined with a dynamical treatment of phonons and excitons and furthermore generalized to the whole variety of realistic QD geometries. Electric fields of different form and strength for the optical control of energy transfer processes will be tested. The number of correlated electrons in the QDs will successively increase, requiring a transition from MCTDH to more efficient, presumably Gaussian-based methods for electron dynamics. With that the corner stone for a general electron dynamical treatment of ultrafast, long-range electron and energy transfer processes in realistic arrays of QDs - and moreover atoms and molecules - is placed. The expected results will furthermore serve to motivate technological use of the processes, i.e. the interatomic Coulombic electron capture (ICEC) for the generation of slow electrons and ICD for infrared photodetectors.