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

• Applicant: Professorin Dr. Annika Bande
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: from 2013 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 242916180

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.

• DFG Programme: Research Grants