Magnetism in Cr-doped ZnS: density-functional theory studies

We investigated the magnetism and aggregation trends in cubic Zn1−xCrxS using density-functional theory calculations. We demonstrate that all studied configurations show ground state half-metallic ferromagnetism (HMF), and Cr impurities are energetically favourable for planar clustering into delta-doping structures. The single-layer delta-doping structures of Zn0.75Cr0.25S and Zn0.875Cr0.125S show ferromagnetic stabilization energies (ΔEAF) of 0.551 eV and 0.561 eV per Cr–Cr pair, respectively. The half-layer delta-doping structure of Zn0.875Cr0.125S and the double-layer delta-doping structure of Zn0.75Cr0.25S show ΔEAF of 0.394 eV and 0.166 eV per Cr–Cr pair, respectively. Furthermore, our studies indicate that the cubic ZnS/CrS heterostructure, one extreme situation of the delta-doping structure, also shows ground state HMF. The origin of HMF is discussed using a simple crystal field model. Finally, we anticipate the potential spintronics application of Zn1−xCrxS.