Evidence of the third $(A^+)$ level of the mercury vacancy in Cd$_x$Hg$_{1-x}$Te

The existence of a previously unknown shallow acceptor level (depth of $\sim$1 meV), which belongs to the intrinsic defect of the semiconductor crystal rather than to the impurity, is found for Cd$_x$Hg$_{1-x}$Te compounds. It is concluded from analysis of the experimental data that this state is the third level of the mercury vacancy $V_{\mathrm{Hg}}$, which emerges due to the capture of an additional hole (state $A^+$).