Interdependence of ICD rates in paired quantum dots on geometry

5 years ago

Interdependence of ICD rates in paired quantum dots on geometry

Fabian Weber, Annika Bande, Emad F. Aziz

Using state-of-the-art antisymmetrized multiconfiguration time-dependent Hartree (MCTDH) electron dynamics calculations we study the interdependence of the intermolecular Coulombic decay (ICD) process on the geometric parameters of a doubly-charged paired quantum dot (PQD) model system in the framework of the effective mass approximation (EMA). We find that ICD displays a maximum rate for a certain geometry of the electron-emitting quantum dot, which is simultaneously dependent on both the distance between the quantum dots as well as the photon-absorbing quantum dot's geometry. The rate maximum is shown to be caused by the competing effects of polarization of electron density and Coulomb repulsion. The ICD rate-maximized PQD geometry in GaAs QDs yields a decay time of 102.39 ps. It is given by two vertically-aligned cylindrical QDs with radii of 14.42 nm separated by 86.62 nm. The photon absorbing QD then has a height of 46.59 nm and the electron emitting QD a height of 16.33 nm. © 2017 Wiley Periodicals, Inc. Using electron dynamics calculations, the intermolecular Coulombic decay (ICD) rate in a paired quantum dot (PQD) model system is optimized by a multidimensional scan of geometric parameters. An ICD rate-limiting maximum is found that is non-trivially interdependent on all geometric parameters. The reason for the occurence of the maxima is identified as the competing effects between Coulomb repulsion and electronic polarization, which expands the understanding of the ICD process in QDs.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/jcc.24843