Influence of external electric field on the shallow donor impurity states in a double parabolic quantum dot
Micro and Nanostructures, cilt.218, sa.208836, ss.1-18, 2026 (SCI-Expanded)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 218 Sayı: 208836
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.micrna.2026.208836
- Dergi Adı: Micro and Nanostructures
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED)
- Sayfa Sayıları: ss.1-18
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Akdeniz Üniversitesi Adresli: Evet
Özet
We present a theoretical investigation of the confined electronic states in a two-dimensional double parabolic quantum dot subjected to external electric fields and Coulomb impurities within the effective-mass approximation. The electronic spectrum is analyzed as a function of the confinement geometry, impurity configuration, electric-field magnitude, and field orientation. The confinement potential enables a continuous transition from a strongly coupled double-quantum-dot regime with pronounced central barriers and localization effects to a single-dot-like flat-bottom confinement profile.
The results reveal that the interplay between confinement topology, impurity-induced asymmetry, and external electric fields strongly modifies the confined energy spectrum. In asymmetric impurity configurations, the breaking of inversion symmetry induces pronounced linear contributions to the quantum-confined Stark effect, whereas symmetric Coulomb configurations restore predominantly quadratic Stark behavior governed by the polarizability of the confined states. The calculations further show the emergence of field-induced anticrossings, electric-field-controlled hybridization between low-lying states, and angular modulation of the electronic energies associated with the vectorial nature of the applied field.
The study also demonstrates that the geometrical parameters controlling the central barrier and the flat-bottom confinement significantly influence localization properties, tunneling coupling, and the compression of excited-state spectra at high electric fields. These results provide a detailed understanding of the combined role of geometry, impurity distribution, and external perturbations in tailoring the electronic structure of low-dimensional semiconductor nanostructures and establish a theoretical framework that may be useful for future investigations of field-controlled quantum devices and related optical phenomena.