Relation between spin-orbit induced spin polarization, Fano-effect and circular dichroism in soft x-ray photoemission.

A Feynman diagram analysis of photoemission probabilities suggests a relation between two final-state spin polarization effects, the optical spin-orientation originating from the interaction with circularly polarized light ([Formula: see text], Fano effect) and the spin polarization induced by the spin-orbit scattering ([Formula: see text], Mott effect). The analysis predicts that [Formula: see text] is proportional to the product of [Formula: see text] and the circular dichroism in the angular distribution (CDAD) of photoelectrons. To confirm this prediction, the spin polarization of photoelectrons excited by soft x-ray radiation from initial spin-degenerate bulk states of tungsten using time-of-flight momentum microscopy with parallel spin detection has been measured.

Nonlocal electron correlations in an itinerant ferromagnet.

Our understanding of the properties of ferromagnetic materials, widely used in spintronic devices, is fundamentally based on their electronic band structure. However, even for the most simple elemental ferromagnets, electron correlations are prevalent, requiring descriptions of their electronic structure beyond the simple picture of independent quasi-particles. Here, we give evidence that in itinerant ferromagnets like cobalt these electron correlations are of nonlocal origin, manifested in a complex self-energy Σ(E,k) that disperses as function of spin σ, energy E, and momentum vector k.

Evidence for in-gap surface states on the single phase SmB(001) surface.

Structural and electronic properties of the SmB(001) single-crystal surface prepared by Ar ion sputtering and controlled annealing are investigated by scanning tunneling microscopy. In contrast to the cases of cleaved surfaces, we observe a single phase surface with a non-reconstructed p(1 × 1) lattice on the entire surface at an optimized annealing temperature. The surface is identified as Sm-terminated on the basis of spectroscopic measurements.

Optical Generation of Hot Spin-Polarized Electrons from a Ferromagnetic Two-Dimensional Electron Gas.

Linearly polarized light with an energy of 3.1 eV has been used to excite highly spin-polarized electrons in an ultrathin film of face-centered-tetragonal cobalt to majority-spin quantum well states (QWS) derived from an sp band at the border of the Brillouin zone. The spin-selective excitation process has been studied by spin- and momentum-resolved two-photon photoemission.

Quantitative spin polarization analysis in photoelectron emission microscopy with an imaging spin filter.

Using a photoelectron emission microscope (PEEM), we demonstrate spin-resolved electron spectroscopic imaging of ultrathin magnetic Co films grown on Cu(100). The spin-filter, based on the spin-dependent reflection of low energy electrons from a W(100) crystal, is attached to an aberration corrected electrostatic energy analyzer coupled to an electrostatic PEEM column. We present a method for the quantitative measurement of the electron spin polarization at 4 × 10³ points of the PEEM image, simultaneously.