Electric control of the exciton fine structure in nonparabolic quantum dots

Welander, Erik; Burkard, Guido

doi:10.1103/physrevb.86.165312

Cited by 9 publications

(8 citation statements)

References 22 publications

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“…The exact analytic formula derived in eqn (5) is useful to understand how energy is stored in multi-layered capacitive nanostructures that interact electrostatically. [10][11][12][13] The expression for the energy stored in a parallel-plate nanocapacitor can be readily used to derive an analytic formula for the capacitance of such a nanocapacitor model. When considering a nanocapacitor with a dielectric lm between the plates, one assumes a phenomenological size/thickness-dependent relative nanopermittivity for the dielectric material that is not the same as the bulk value.…”

Section: Discussionmentioning

confidence: 99%

Origin of the anomalous size-dependent increase of capacitance in boron nitride–graphene nanocapacitors

Ciftja

2019

RSC Adv.

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The anomalous size-dependent increase in capacitance in boron nitride-graphene nanocapacitors is a puzzle that has been initially attributed to the negative quantum capacitance exhibited by this particular materials system. However, we show in this work that the anomalous nanocapacitance of this system is not due to quantum effects but has pure electrostatic origin and can be explained by a parallel-plate (square) nanocapacitor model filled with a dielectric film characterized by a size/thickness-dependent relative permittivity. The model presented here is in excellent agreement with the experimentally measured capacitance values of recently fabricated graphene and hexagonal boron nitride nanocapacitors. The results obtained seem to suggest that the size-dependent increase of capacitance in the above-mentioned family of nanocapacitors can be explained by classical finite-size geometric electrostatic effects.

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Section: Discussionmentioning

confidence: 99%

Origin of the anomalous size-dependent increase of capacitance in boron nitride–graphene nanocapacitors

Ciftja

2019

RSC Adv.

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“…As a second example, we graphically displayed the relative energy difference between the exact expression and its macroscopic counterpart showing that the macroscopic formula should be used with extreme caution and only when the spacing between the two circular plates is very small, in the order of less than

relative to the radius. The exact analytic formula shown in Equation ( 13 ) can help understand how the energy is stored in multi-layered capacitive nanostructures with circular symmetry [ 49 , 50 , 51 , 52 , 53 ].…”

Section: Discussionmentioning

confidence: 99%

Energy Stored and Capacitance of a Circular Parallel Plate Nanocapacitor

Ciftja

2021

Nanomaterials

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Nanocapacitors have received a great deal of attention in recent years due to the promises of high energy storage density as device scaling continues unabated in the nanoscale era. High energy storage capacity is a key ingredient for many nanoelectronic applications in which the significant consumption of energy is required. The electric properties of a nanocapacitor can be strongly modified from the expected bulk properties due to finite-size effects which means that there is an increased need for the accurate characterization of its properties. In this work, we considered a theoretical model for a circular parallel plate nanocapacitor and calculated exactly, in closed analytic form, the electrostatic energy stored in the nanocapacitor as a function of the size of the circular plates and inter-plate separation. The exact expression for the energy is used to derive an analytic formula for the geometric capacitance of this nanocapacitor. The results obtained can be readily amended to incorporate the effects of a dielectric thin film filling the space between the circular plates of the nanocapacitor.

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“…Bryant et al [17] implemented a nanomechanical strain to theoretically engineer the fine structure splitting of quantum dots for quantum processing using the tight-binding theory. Welander and Burkard [18] theoretically reported that a finite applied electric field was used to suppress the fine structure splitting in nonparabolic quantum dots. Sinito et al [19] demonstrated that it was possible to manipulate the fine structure splitting using an external magnetic field which could be used to tailor the properties of entangled photon sources.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Tight-Binding Theory of Electron-Hole Exchange Interaction in Morphological Evolution of CdSe/ZnS Core/Shell Nanodisk to CdSe/ZnS Core/Shell Nanorod

Sukkabot

2016

Journal of Nanomaterials

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Based on the atomistic tight-binding theory (TB) and a configuration interaction (CI) description, the electron-hole exchange interaction in the morphological transformation of CdSe/ZnS core/shell nanodisk to CdSe/ZnS core/shell nanorod is described with the aim of understanding the impact of the structural shapes on the change of the electron-hole exchange interaction. Normally, the ground hole states confined in typical CdSe/ZnS core/shell nanocrystals are of heavy hole-like character. However, the atomistic tight-binding theory shows that a transition of the ground hole states from heavy hole-like to light hole-like contribution with the increasing aspect ratios of the CdSe/ZnS core/shell nanostructures is recognized. According to the change in the ground-state hole characters, the electron-hole exchange interaction is also significantly altered. To do so, optical band gaps, ground-state electron character, ground-state hole character, oscillation strengths, ground-state coulomb energies, ground-state exchange energies, and dark-bright (DB) excitonic splitting (stoke shift) are numerically demonstrated. These atomistic computations obviously show the sensitivity with the aspect ratios. Finally, the alteration in the hole character has a prominent effect on dark-bright (DB) excitonic splitting.

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Electric control of the exciton fine structure in nonparabolic quantum dots

Cited by 9 publications

References 22 publications

Origin of the anomalous size-dependent increase of capacitance in boron nitride–graphene nanocapacitors

Origin of the anomalous size-dependent increase of capacitance in boron nitride–graphene nanocapacitors

Energy Stored and Capacitance of a Circular Parallel Plate Nanocapacitor

Atomistic Tight-Binding Theory of Electron-Hole Exchange Interaction in Morphological Evolution of CdSe/ZnS Core/Shell Nanodisk to CdSe/ZnS Core/Shell Nanorod

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