Tunable optical properties and impurity binding energy in Shifman-type quantum wells under an external electric field
European Physical Journal Plus, cilt.141, sa.7, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 141 Sayı: 7
- Basım Tarihi: 2026
- Doi Numarası: 10.1140/epjp/s13360-026-08006-8
- Dergi Adı: European Physical Journal Plus
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sivas Cumhuriyet Üniversitesi Adresli: Evet
Özet
This paper presents a theoretical investigation into the electronic and optical properties of a quantum well defined by the hyperbolic Shifman potential. Using the effective mass approximation, we analyze the influence of an external electric field and donor impurities on the system’s energy levels and absorption characteristics. To solve the Schrödinger equation of the system, the diagonalization method was utilized by choosing orthonormal base functions. The variational method for impurity binding energy is used. The results demonstrate that the Shifman potential offers structural versatility; by modulating the structure parameter, the confinement profile can be tuned from a single to a symmetric double quantum well. An external electric field induces a significant quantum-confined Stark effect, breaking spatial symmetry and allowing for precise control over wave function localization and energy subband spacing. Impurity binding energy directly reflects the ground-state wave function distribution of the electron in the quantum well. Impurities at positions where the probability density is maximum possess a larger binding energy due to the strong Coulomb attraction. Under an electric field, this maximum shifts toward the left, following the field-induced redistribution of the wave function. Additionally, the 1s state exhibits a greater binding energy than the 2s state due to its stronger spatial confinement. Also, we examine the linear and third-order nonlinear absorption coefficients for both intraband (1–2) and impurity-related (1s–2s) transitions. The optical transitions between any two states were calculated by using the density matrix formalism and the perturbation expansion method. Our results show that the optical response is highly sensitive to the well width and the spatial position of the donor impurity. Specifically, double-well configurations are found to enhance nonlinear effects, such as absorption saturation and bleaching. The identified energy transitions for wider well configurations fall primarily within the far-infrared and terahertz regimes.