QUANTUM-DIMENSIONAL STARK EFFECT IN THE SPECTRA OF DOUBLE PHOTO-IONIZATION OF TWO-ELECTRON IMPURITY CENTERS IN QUASIZERO-DIMENSIONAL STRUCTURES
Background. The presence of single impurity centers in quantum dots can have a significant impact on their electronic and optical properties. The study of the possibility of controlling the binding energy of impurity centers by varying external electric or magnetic fields is an urgent task. Two-electron centers attract particular attention because of the possibility of observing double photoionization, which can provide valuable information about electron-electron correlations in quasizero-dimensional structures. The aim of this work is to theoretically study the influence of an external electric field on the spectra of double photoionization of two-electron impurity centers in a semiconductor quasizero-dimensional structure. Materials and methods. The influence of the external electric field was carried out in the framework of the perturbation theory. The calculation of the binding energy and the first ionization potential of a two-electron impurity atom was carried out by the variational method, where the second ionization potential was taken as an empirical parameter. The expression for the coefficient of extrinsic absorption of light was obtained in the dipole approximation taking into account the dispersion of the radius of quantum dots. Results. It is shown that with an increase in the intensity of the external electric field, the threshold value of the second ionization potential increases, starting from which the existence of a two-electron bound state is possible due to electron polarization and a Stark energy shift, which is accompanied by the strengthening of electron correlations. It was found that, in the spectra of double photoionization, the strengthening of electron correlations is accompanied by a Stark shift of the spectral curves and their pronounced two-humped profile. Conclusions. In an external electric field, additional degrees of freedom appear to control electronic correlations in the spectra of double photoionization of quasizero-dimensional structures.