Modifications in the photoionization cross-section of a quantum dot with position-dependent effective mass

Abstract

In this work, we investigate the photoionization cross-section of an electron confined in a quantum dot, considering the position-dependent variation of the effective mass through the parameter $\gamma$. We used a theoretical model based on the Schr\"odinger equation, in which $\gamma$ influences the energy levels and wave functions through an effective potential obtained from the harmonic oscillator potential - which, in the limit $\gamma = 0$, reduces to the original harmonic oscillator potential. Furthermore, we compared the modifications in the photoionization cross-section of these quantum systems with the constant-mass case. Our results demonstrate that even a small variation in $\gamma$ significantly impacts the photoionization process's amplitude and peak position. We also found that for specific values of $\gamma$, an inversion occurs: The amplitude, which initially increases as the quantum dot absorbs the photon, begins to decrease. Additionally, we observed that the optical transitions involving the ground state restrict the admissible values of $\gamma$ to negative values only. These results may have relevant implications for designing optoelectronic devices based on quantum dots with adjustable mass properties.