Density functional theory (DFT) within the generalized gradient approximation (GGA) has been used to study the structural and electronic properties of
Eu3þ defect complexes in GaN under Ga-rich conditions. Two distinct configurations of the EuGaVN defect complex, the axial and basal configuration, have
been investigated. We report two forms of metastable defects namely; the Negative U defect in the lower half of the GaN band-gap and a metastable defect
with two distinct configurations each with levels at EC 0.46 eV and 0.56 eV in the upper half of the GaN band-gap.