Investigations on the local structure and EPR parameters for the trigonal Nd3+ centre in CdS

Abstract

The local structure and the electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants) for the trigonal Nd3+ centre in CdS are theoretically investigated by considering the local lattice relaxation. The impurity Nd3+ is found not to occupy exactly the host Cd2+ site, but to suffer a shift of about 0.31 Å away from the sulphide triangle along the C3 axis due to size and charge mismatch. The theoretical EPR parameters based on the above impurity axial displacement are in good agreement with the observed values. The local structure and the EPR parameters are discussed for this centre.