Interdependence of ICD rates in paired quantum dots on geometry

Abstract

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.

Quantum size effect affecting environment assisted electron capture in quantum confinements

“…As a consequence of the quantum-size effect, ICD and ICEC must depend on the size of the electronic confinements which has been investigated in the case of ICD. 53,54 Here, we intend to use the effect to study the particular interplay between ICD and ICEC, whereas a following empirical high-throughput study on ICEC in quantum dots will disentangle the particular dependence of maximal ICEC probability density on eigenenergy interrelations. 47 The primary interest in the present study is the electron…”

Predicting the performance of the inter-Coulombic electron capture from single-electron quantities

“…Geometry variations of the individual QDs foster changes of the electronic structure (known as the quantum-size effect [18][19][20]) which, in turn, alter ICD. This was systematically analyzed taking into account the non-trivial interdependence of several geometric parameters [37][38][39]. First hints on how geometry changes also ICEC have already been collected in computations on nanowire-embedded paired n-doped QDs [33,36,40].…”

Acoustic phonon impact on the inter-Coulombic decay process in charged quantum dot pairs

“…(10) phonons lead to potential depth variation which stands for a material change by either doping or by distortion of the elementary cell. Another possible and equally meaningful implementation is a periodic change of b k reflecting the QDs' heights [81,83]. For the harmonic oscillator confinement potentials in the x and y direction the targeted oscillation of the energetic level landscape is realized by…”

“…Due to the boundary conditions of ICD, the paired QDs are largely decoupled from each other [81,83]. However, in account for the remaining low probability for tunnelling of electrons among the dots and due to the possible longer distance of interactions involving phonons, it is essential to consider the influence of the respective neighbouring QD, may it be still or vibrating, when investigating the phonon dissipation of the A 1 or E 0 electron.…”

“…In a series of papers on pairs of singly-charged QDs, we particularly elucidated the electron dynamics of ICD [69,[80][81][82][83][84] with highly-accurate MCTDHF-like calculations [85,86] (multiconfiguration time-dependent Hartree-Fock). Motivation for this attempt has always been the curiosity in the time development of the electronic situation which cannot be addressed neither by non-Hermitian electronic structure theory for resonances [87][88][89][90] nor by nuclear dynamics of the cluster explosion after ICD [91][92][93] otherwise used in the prediction of ICD rates.…”