Thermodynamic properties of electron–phonon in a GaAs quadratic quantum dot potential in the presence of impurity and external fieldsL. M. Taguefouet, M. Silenou Mengoue, A. J. Fotue and M. F. C. FobassoEur. Phys. J. Plus, 137 5 (2022) 530DOI: https://doi.org/10.1140/epjp/s13360-022-02698-4