Zero-field splittings and local tilting angles τMn2+τMn2+ for Mn2+ in ZnGeP2 and CdGeP2 crystals

The electron paramagnetic resonance (EPR) zero-field splittings (ZFSs) D of Mn2+ in ZnGeP2 and CdGeP2 crystals are calculated from both the microscopic spin–orbit coupling mechanism and the empirical superposition model. From the calculations, the ZFS D of ZnGeP2:Mn2+ is reasonably explained by using the local tilting angle τMn2+τMn2+ (rather than the corresponding angle τZn2+τZn2+ in the host crystal) and the local tilting angle τMn2+τMn2+ (which has not been reported) in CdGeP2:Mn2+ is estimated. The intrinsic ZFS parameter b¯2(R0)≈−0.052(6) cm−1 (with R0 ≈ 2.43 Å) is suggested for Mn2+–P3− combination by using the local tilting angles τMn2+τMn2+. The value is quite unlike that (≈0.4(2) cm−1) obtained in the previous paper by combining the crystallographic data of host crystals with the ZFSs for Mn2+ ions in crystals. The reasonableness of these results is discussed.