The splitting patterns of point defect energy levels in wurtzite crystals under uniaxial stress are derived for stress applied along an arbitrary crystal direction. The nonsymmorphic wurtzite crystal has a hexagonal point group $C_{6v}$, while point defects in the crystal belong to one of either the trigonal ($C_{3v}$ and $C_3$), monoclinic $\left(C_{1h}\right)$, or triclinic $\left(C_1\right)$ symmetry classes. Trigonal defects may possess both intrinsic and orientational degeneracies (apart from time-reversal degeneracy), while the monoclinic and triclinic defects possess only orientational degeneracy (again neglecting time-reversal degeneracy). The splitting patterns of the energy levels of defects belonging to these classes are derived for uniaxial stress along arbitrary directions and the contributions to the various stress-split components from the different inequivalent orientations are indicated. The results of the theoretical analyses are compared with a selection of experimental results from the literature and good agreement is found in all cases. The general equations provided here should prove to be very valuable for the interpretation of uniaxial stress data for all wurtzite crystals.

• Received 3 August 2007

DOI:https://doi.org/10.1103/PhysRevB.76.184109