Structural, electronic and magnetic properties of Co nRh ( n=1–8) clusters from density functional calculations

Abstract

The geometries, stabilities, electronic and magnetic properties of Co n Rh ( n=1–8) clusters have been investigated systematically within the framework of the generalized gradient approximation density-functional theory. The results indicate that the most stable structures of Co n Rh ( n=1–8) clusters are all similar to those of corresponding Co n+1 clusters. Maximum peaks of second-order energy difference are found at n=2, 4 and 7, indicating that these clusters possess relatively higher stability than their respective neighbors. The magnetism of the ground state of alloy clusters all displays ferromagnetic coupling except for Co 3Rh. In addition, the doped Rh atom exhibits an important influence on the magnetism of alloy clusters, e.g., compared with corresponding pure Co n clusters, the local moment of Co atom is noticeably enhanced in Co n Rh alloy clusters at n=1, 2, 5, 6, 7 and 8, while reduced at n=3 and 4. Further analysis based on the average bond length, the charge transfer and the spin polarization has been made to clarify the different magnetic responses to Rh doping.