Charge state splittings of deep levels in Hg₁__xCd_xTe

The charge state splittings of the deep levels produced by singly ionized, substitutional impurities on both the cation (Hg/Cd) and the anion (Te) sites in Hgi.CdTe are investigated using a Green's function formalism. With this approach, the defect potential, the deep level, and the charge density on the impurity and its nearest-neighbor sites are determined self-consistently in a tight-binding basis. Results are presented for the charge state splittings of the s_x/2-like levels associated with positively charged impurities on the cation site and of the p_1/2-like levels associated with negatively charged impurities on the anion site. In all cases investigated, the splittings are found to be of the order of 0.1 to 0.2 eV and to decrease with decreasing alloy composition (;c).