Exciton–phonon properties in cylindrical quantum dot with parabolic confinement potential under electric field

Mommadi, Omar; Moussaouy, A. El; Chnafi, M.; Hadi, Mohamed El; Nougaoui, A.; Magrez, H.

doi:10.1016/j.physe.2019.113903

Cited by 33 publications

(17 citation statements)

References 49 publications

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“…The study of low-dimensional semiconductor heterostructures (LDSH) has gained relevance due to their high-efficient optoelectronic properties. In accordance, numerous theoretical and experimental studies have been performed [ 1 , 2 , 3 , 4 , 5 ]. Among these structures it is possible to mention the quantum wells (with charge carrier confinement along one dimension), quantum wires (confinement in two dimensions), and quantum dots (QDs).…”

Section: Introductionmentioning

confidence: 88%

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

et al. 2023

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A theoretical analysis of optical properties in a ZnS/CdS/ZnS core/shell/shell spherical quantum dot was carried out within the effective mass approximation. The corresponding Schrödinger equation was solved using the finite element method via the 2D axis-symmetric module of COMSOL-Multiphysics software. Calculations included variations of internal dot radius, the application of electric and magnetic fields (both oriented along z-direction), as well as the presence of on-center donor impurity. Reported optical properties are the absorption and relative refractive index change coefficients. These quantities are related to transitions between the ground and first excited states, with linearly polarized incident radiation along the z-axis. It is found that transition energy decreases with the growth of internal radius, thus causing the red-shift of resonant peaks. The same happens when the external magnetic field increases. When the strength of applied electric field is increased, the opposite effect is observed, since there is a blue-shift of resonances. However, dipole matrix moments decrease drastically with the increase of the electric field, leading to a reduction in amplitude of optical responses. At the moment impurity effects are activated, a decrease in the value of the energies is noted, significantly affecting the ground state, which is more evident for small internal radius. This is reflected in an increase in transition energies.

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Section: Introductionmentioning

confidence: 88%

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

et al. 2023

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“…The above-mentioned characteristics prove the contribution of the exciton-polaron to the dynamics of a given system. This concept is well known in the context of nanostructure dynamics ( Mommadi et al, 2020 ), but to our knowledge, it has not yet been studied in the context of microtubule dynamics. MTs consist of dynamically aggregated proteins that move with the phenomena of polymerization and depolymerization, maintaining the mechanical stability of the cell.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of exciton polaron in microtubule

Nganfo

Kenfack-Sadem

Fotué

et al. 2022

Heliyon

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In this paper, we study the dynamical properties of the exciton-polaron in the microtubule. The study was carried out using a unitary transformation and an approximate diagonalization technique. Analytically, the modeling of exciton-polaron dynamics in microtubules is presented. From this model, the ground state energy, mobility, and entropy of the exciton-polaron are derived as a function of microtubule's parameters. Numerical results show that, depending on the three vibrational modes (protofilament, helix, antihelix) in MTs, exciton-polaron energy is anisotropic and is more present on the protofilament than the helix and absent on the antihelix. Taking into account the variation of the protofilament vibrations by fixing the helix vibrations, exciton-polaron moves between the 1st and 2nd protofilaments. It is seen that the variation of the two vibrations induces mobility of the quasiparticle between the 1st and 15th protofilament. This result points out the importance of helix vibrations on the dynamics of quasiparticles. It is observed that the mobility of the exciton polaron and the entropy of the system are strongly influenced by the vibrations through the protofilament and helix. The effects of the one through the antihelix is negligible. The entropy of the system is similar to that of mobility. Confirming that the quasiparticles move in the protofilament faster than in the helix.

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“…The confinement of charge carriers into the QD, according to two or three spatial directions, has many advantages in terms of control of their electronic and binding energies as well as their linear and nonlinear optical properties. It allows for better optimization of photophysical properties according to the shape and the QD size [ 21 , 22 , 23 , 24 , 25 ]. Due to the symmetric wave function, under linear and circularly polarized incident radiation, when the QD size changes under the condition of fixed geometry, small changes in the amplitude of the resonance peak and the progressive redshift of the curve can be identified.…”

Section: Introductionmentioning

confidence: 99%

First Study on the Electronic and Donor Atom Properties of the Ultra-Thin Nanoflakes Quantum Dots

et al. 2022

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Nanoflakes ultra-thin quantum dots are theoretically studied as innovative nanomaterials delivering outstanding results in various high fields. In this work, we investigated the surface properties of an electron confined in spherical ultra-thin quantum dots in the presence of an on-center or off-center donor impurity. Thus, we have developed a novel model that leads us to investigate the different nanoflake geometries by changing the spherical nanoflake coordinates (R, α, ϕ). Under the infinite confinement potential model, the study of these nanostructures is performed within the effective mass and parabolic band approximations. The resolution of the Schrödinger equation is accomplished by the finite difference method, which allows obtaining the eigenvalues and wave functions for an electron confined in the nanoflakes surface. Through the donor and electron energies, the transport, optoelectronic, and surface properties of the nanostructures were fully discussed according to their practical significance. Our findings demonstrated that these energies are more significant in the small nanoflakes area by altering the radius and the polar and azimuthal angles. The important finding shows that the ground state binding energy depends strongly on the geometry of the nanoflakes, despite having the same surface. Another interesting result is that the presence of the off-center shallow donor impurity permits controlling the binding energy, which leads to adjusting the immense behavior of the curved surface nanostructures.

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Exciton–phonon properties in cylindrical quantum dot with parabolic confinement potential under electric field

Cited by 33 publications

References 49 publications

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

Dynamics of exciton polaron in microtubule

First Study on the Electronic and Donor Atom Properties of the Ultra-Thin Nanoflakes Quantum Dots

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