The Electronic Structure and Magnetism of bcc Rh(001) Surface

According to the recent reports the bulk bcc Rh is ferromagnetic with a small difference of energy compared to paramagnetic state. In this study, the electronic structure and magnetism for bcc Rh(001) surface are investigated by means of the all-elec-tron full potential linearized augmented plane wave method within the generalized gradient approximation. It is found that the surface ferromagnetic state is preferable over the paramagnetic one. For unrelaxed system, the magnetic moment of the sur-face layer, 0.48 µ B, is slightly increased comparing with the bulk value, 0.41 µ B while the value of the subsurface layer, 0.23 µ B, is much smaller than the bulk value. The total energy and atomic force calculations show that the surface layer is relaxed downward and the subsurface layer moves upward to reduce the layer distance between the surface and subsurface layers by 7.0 %. The relaxation effect leads to weakening the surface magnetic properties. Specifically, the value of the mag-netic moment of the surface atom is decreased to 0.36 µ B. Since the spin polarization of the subsurface layer is only 0.14 µ B, it is concluded that the bcc Rh(001) surface is rather weakly ferromagnetic