Influences of temperature and impurity on excited state of bound polaron in the parabolic quantum dots

• The temperature effect of quantum dot is studied.
• Confinement strength of first excited state and excitation energy is found.
• Confinement strength of the transition frequency is found.
• The relation of first excited state and Coulombic impurity potential.
• Three ways of tuning the quantum dot parameters are studied.

On the condition of strong electron-LO phonon coupling in parabolic quantum dot (QD), the first excited state energy, the excitation energy and the transition frequency between the first excited and the ground states of the bound polaron are calculated by using the linear combination operator and the unitary transformation methods. The variation of the above quantities with the temperature, the Coulombic impurity potential and the QD confinement strength are studied in detail. We find that (1) These physical quantities will increase with increasing temperature. (2) They are increasing functions of the confinement strength due to the existence of the Coulombic impurity potential between the electron and the hydrogen-like impurity. (3) We obtain three ways of tuning them via controlling the temperature, the Coulombic impurity potential and the confinement strength.