Magnetism of Gadolinium: A First-Principles Perspective

By calculating the spectral density of states in the ferromagnetic ground state and in the high temperature paramagnetic phase we provide the first concise study of finite temperature effects on the electronic structure of the bulk and the surface of gadolinium metal. The variation of calculated spectral properties of the Fermi surface and the density of states in the bulk and at the surface are in good agreement with recent photoemission experiments performed in both ferromagnetic and paramagnetic phases. In the paramagnetic state we find vanishing spin splitting of the conduction band, but finite local spin moments both in bulk and at the surface. We clearly demonstrate that the formation of these local spin moments in the conduction band is due to the asymmetry of the density of states in the two spin channels, suggesting a complex, non-Stoner behavior. We, therefore, suggest that the vanishing or nearly vanishing spin splitting of spectral features cannot be used as an indicator for Stoner-like magnetism.

Figure 1

(a) Spin resolved spectral DOS of the ferromagnetic phase and (b) total spectral DOS of the paramagnetic phase of bulk gadolinium at the Fermi energy as projected to the 2D Brillouin zone. Darker colors represent larger values of the spectral DOS.

Figure 2

Spin resolved densities of states in Gd bulk and in the top layer of the Gd(0001) surface in the (a) ferromagnetic and (b) paramagnetic phase.

Figure 3

Spectral densities of states evaluated at the Fermi energy in the ferromagnetic (top row) and paramagnetic (bottom row) phases for Gd bulk and the first six layers below a Gd(0001) surface.