Interparticle Coulombic Decay Dynamics along Single- and Double-Ionization Pathways

Abstract

The interparticle Coulombic decay process (ICD) in a Coulomb-coupled pair of quantum dots (QDs) was predicted to feature electronic relaxation within one QD in conjunction with ionization of the other. In this work the QD model is extended from a pair to a triad of one excited and two ionizable QDs and in total three electrons. Analytical Wigner-Weisskopf expressions for the decay rates are formulated and confirmed with numerical electron dynamics calculations, suggesting a rate enhancement by a factor two that may be relevant for the competitiveness of ICD in QDs. Particularly, we compare two energetic scenarios, one allowing only for single ionization of the QD triad and one, not yet discussed in the community, potentially allowing for double ionization.

Three-electron dynamics of the interparticle Coulombic decay with two-dimensional continuum confinement

“…another QD of the same material as the others, it acts as a participator in a three-electron ICD process. 50 This means among others that it supports the prefactor for the number of neighbors N predicted from the aforementioned analytical rate equation. 39,40 Just recently, the ICD rate equation was also confirmed in electron dynamics calculation in two-electron systems with a two-dimensional electronic continuum.…”

“…For the realm of electron dynamics calculations in QD models, this attempt is a novelty, because it bridges among knowledge on three electrons in three sites 50 and knowledge on a twodimensional continuum. 48,51 We anticipate a reduction of rate fluctuations and an increase of the rate by a factor of two compared to the ICD rate with one neighbor only.…”

Interatomic and Intermolecular Coulombic Decay

“… 79 , 476 Thus, in the three-dot array, the computed ICD rate is twice the rate of the two-dot array. 477 …”

“…The rate for three site dICD was recently shown to vanish from an orbital overlap argument in a theoretical work about a triad of quantum dots. 477 To clarify the apparent contradiction to the experimental results is beyond the scope of this review; however, we would like to mention that atomic processes that are enabled by deviations from strict orbital orthogonality, so-called shake transitions, are observed in electron emission experiments in numerous settings. It is also interesting to compare collective ICD processes detailed above, and the three-electron ICD 23 ( Section 5.1.8 ) to collective Auger processes in atoms and molecules, which were recently summarized.…”

Wavepacket golden rule treatment of interparticle Coulombic decay in paired quantum dots

“…(i) the dependence of the decay rate on the inter-QD separation and on the shape of the QDs 21,22,24,26,31 , (ii) the existence and effect of shape resonances 27 , leading to preferential directions for electron emission as well as the dependence of the right-to-left partial decay width on the inter-QD distance 22 , (iii) the excitation by laser pulses, the presence of Rabi-oscillations and the role of multiphoton processes 23,25,31,32 , (iv) the impact of acoustic phonons 33 , (v) the role of additional ionization channels in a three-electron three-QD system 34 .…”