The influence of cluster size and of cluster-substrate interaction on the magnetic properties of Co clusters of 1-10 atoms on Pt(111) and Au(111) is studied by fully relativistic ab initio calculations. The focus is on systematic trends of the spin and orbital magnetic moments, the exchange coupling, and the crossover temperature. The spin magnetic moments of Co clusters are larger for the Pt substrate than for the Au substrate, while the reverse is true for the orbital magnetic moments. The local magnetic moments of Co atoms generally increase if the number of Co neighbours decreases. The exchange coupling constants J i j depend on the cluster size and on the location of respective atoms. The crossover temperature increases monotonically with cluster size and is larger for clusters on Pt than for clusters on Au.

We present a detailed theoretical investigation on the magnetic properties of small single-layered Fe, Co and Ni clusters deposited on Ir(111), Pt(111) and Au(111). For this a fully relativistic abinitio scheme based on density functional theory has been used. We analyse the element, size and geometry specific variations of the atomic magnetic moments and their mutual exchange interactions as well as the magnetic anisotropy energy in these systems. Our results show that the atomic spin magnetic moments in the Fe and Co clusters decrease almost linearly with coordination on all three substrates, while the corresponding orbital magnetic moments appear to be much more sensitive to the local atomic environment. The isotropic exchange interaction among the cluster atoms is always very strong for Fe and Co exceeding the values for bulk bcc Fe and hcp Co, whereas the anisotropic Dzyaloshinski-Moriya interaction is in general one or two orders of magnitude smaller when compared to the isotropic one. For the magnetic properties of Ni clusters the magnetic properties can show quite a different behaviour and we find in this case a strong tendency towards noncollinear magnetism.

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We have studied the evolution of the Pt(111) Shockley-type surface state, which can be described as a surface resonance upon deposition of Ag monolayers. We have combined angle-resolved photoemission and scanning-tunneling-spectroscopy measurements with electronic-structure and photoemission calculations for true semi-infinite systems to guarantee a complete description of all surface-sensitive spectral features. An unusual energy shift and a considerable Rashba-type spin-orbit splitting of the surface resonance were observed and are discussed in terms of modifications in the electronic structure and relationship between the semi-infinite bulk and the surface potential via multiple electron scattering. The maximum magnitude of the splitting in momentum space amounts to 0.051 ± 0.007Å−1 and appears as one of the highest values so far observed in thē -type surface-state-resonance bands.

The spin-orbit coupling can lead to exotic states of matter and unexpected behavior of the system properties. In this paper, we investigate the influence of spin-orbit coupling induced by proximity effects on a monolayer of superconductor (with s-wave or d-wave pairing) placed on an insulating bulk. We show that the critical temperatures Tc of the superconducting states can be tuned by the spin-orbit coupling both in the case of on-site and inter-site pairing. Moreover, we discuss a possibility of changing the location of the maximal Tc from the half-filling into the underdoped or overdoped regimes.