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    Retraction notice to “The combined effects of electric field and embedded dielectric matrix on the electronic and optical properties in Ge/SiGe core/shell quantum dots and its SiGe/Ge inverted structure” [Physics Letters A (2024) 129760] (Physics Letters A (2024) 523, (S0375960124004547), (10.1016/j.physleta.2024.129760))
    (Elsevier B.V., 2025) Hammouda, K.; Yahyaoui, N.; Zeiri, N.; Baser, P.; Duque, C.A.; Murshed, Mohammad N.; Said, M.
    This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). This article has been retracted at the request of the Editor. Post-publication, it came to the attention of the journal that the authors did not obtain the necessary approval from the journal editor for the addition of a new author and a change to the author order, which is contrary to the journal policy on changes to authorship. In addition, the newly added author (Dr. C.A. Duque) had been suggested as a reviewer by the authors at the submission stage. The editor reached out to the authors for an explanation to the above points, but they failed to provide a satisfactory explanation. Overall, the editor believes that adding a new author at the revision stage without obtaining the necessary approval from the journal editor is contrary to the journal policies and decided to retract the paper. © 2025 Elsevier B.V.
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    The combined effects of electric field and embedded dielectric matrix on the electronic and optical properties in Ge/SiGe core/shell quantum dots and its SiGe/Ge inverted structure
    (Elsevier, 2024) Hammouda, K.; Yahyaoui, N.; Zeiri, N.; Başer, Pınar; Duque, C. A.; Murshed, Mohammad N.; Said, M.
    In this study, the binding energy (BE) and photoionization cross-section (PICS) coefficients in a Ge/Si0.15Ge 0.85 core/shell quantum dots (CSQDs) and in its inverted structure Si0.15Ge0.85 / Ge (ICSQDs) are studied. The influence of the hydrogenic impurity and capped matrix are taken into account. The electronic states and their related eigenfunctions are computed by solving the three-dimensional Schrodinger equation under the framework of the effective mass approximation (E.M.A) using the variational dimensional. The influence of the core radius and electric field strength on the BE and PICS are investigated. The numerical results reveal that the optoelectronic properties are considerably affected by the electric field strength (EF), immersed oxide matrix (OM) and geometric parameter. The obtained results prove that the PICS magnitude increases as the core radius increases and its resonant peak moves towards the lower energies for Ge/Si0.15Ge0.85 CSQDs structure, and increases as the core radius decreases and its resonant peak experiences a blue shift with increasing core radius for Si0.15Ge 0.85/ Ge ICSQDs. Moreover, with the effects of the surrounding oxide matrix and electric field strength, the PICS magnitude is improved and their resonant peak suffers a redshift.
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    Third-order nonlinear optical susceptibility of hydrogenic impurity in Ge/ Si0.15Ge0.85 spherical core/shell quantum dots under electric field
    (Pergamon-Elsevier Science Ltd, 2024) Hammouda, K.; Yahyaoui, N.; Zeiri, N.; Ed-Dahmouny, A.; Başer, Pınar; Sali, A.; Said, M.
    In this review, we have investigated theoretically the third-order nonlinear optical susceptibility in Ge/ Si0.15Ge0.85 spherical core/shell quantum dots under electric field (EF) for both cases with and without on -center impurity within the framework of the compact-density-matrix (C.D.M). The eigenenergies and their corresponding wave functions of the system are computed by solving the three-dimensional Schro center dot dinger equation using the effective mass approximation (E.M.A) using the variational method (VM). Our computational results show that both the energy levels and the third-order nonlinear optical susceptibility are strongly affected by the quantum dot size, the effects of the hydrogenic impurity, and the electric field intensity.