Pressure Study of Charged Donor Ordering in HgSe Doped with Iron and Gallium

Transport experiments (Hall effect and conductivity) under hydrostatic pressure up to 1 GPa at liquid helium temperatures on HgSe: Fe, Ga (N$\text{}_{Fe}$ = 2 x 10$\text{}^{19}$ cm$\text{}^{-3}$; 0 ≤ N$\text{}_{Ga}$ ≤ 10$\text{}^{19}$ cm$\text{}^{-3}$) were performed. The results show that the gallium co-doping of HgSe:Fe decreases the degree of spatial correlations between charged impurities. Under the hydrostatic pressure, used as a tool for changing the ratio of the charged to neutral impurities, this effect is even more pronounced. A qualitative agreement between the calculation within the short-range correlation model and our experimental data is achieved.