  We investigate the self-compensation mechanism in phosphorus-doped CdTe. The
formation energies, charge transition levels, and defects states of several
P-related point defects susceptible to cause self-compensation are addressed by
first-principles calculations. Moreover, we assess the in uence of the
spin-orbit coupling and supercell-size effects on the stability of AX centers
donors, which are believed to be responsible for most of the self-compensation.
We report an improved result for the lowest-energy configuration of the P
interstitial (P$_\text{i}$) and find that the self-compensation mechanism is
not due to the formation of AX centers. Under Te-rich growth conditions,
(P$_\text{i}$) exhibits a formation energy lower than the substitutional
acceptor (P$_\text{Te}$) when the Fermi level is near the valence band, acting
as compensating donor. While, for Cd-rich growth conditions, our results
suggest that p-type doping is limited by the formation of
(P$_\text{Te}$-V$_\text{Te}$) complexes.
