Longitudinal spin polarization and symmetries in low-energy-electron diffraction: Experiment and theory for Pt(111)

Abstract

In low-energy electron diffraction from Pt(1 11), the longitudinal component of the spin polarization vector and its transverse component normal to the scattering plane were measured by a Mott detector and found to agree very well with corresponding theoretical results. Rotation diagrams of the longitudinal and transverse components exhibit only a three-fold symmetry in contrast to the six-fold symmetry, which time reversal invariance dictates for intensities.IN ELASTIC electron-atom scattering with an high-precision two-axis manipulator for the Pt(l 11) unpolarized incident beam of momentum k 0, spin-orbit crystal allow to feed selected diffracted beams into the coupling leads to spin polarization such that for polarization analyzer based on Molt scattering at electrons of momentum k the polarization vector is 120 keV [I). On its path between the diffraction sysnormal to the scattering plane defined by k0 and k [11.tern and the Mott-detector, the diffracted beam under In low-energy electron diffraction from crystal surfaces consideration is deflected electrostatically by 90°about of large.Z materials effects of spin polarization normal the axis normal to the scattering plane (k0, k). Since to the scattering plane are well-established the deflection leaves the polarization vector P experimentally and theoretically 121. So far, however, unchanged, the transverse component P~normal to no experimental verification is known for in-plane the scatteringplane (P~= P . n; n = k0 x k/1k0 x ki) components, the existence of which was predicted by remains transverse with respect to the new beam theory [31as a consequence of multiple scattering. We direction, while the initial longitudinal component report here, for diffraction from Pt(l 11), the first P,~= P k/jkl becomes transverse (lying in the paper measurements of a spin polarization component parallel plane, still normal to n). The scattering chamber of the to the scattering plane and compare them to correspond-Mott detector can be rotated about the incoming beam. ing theoretical results. The present spin polarization Setting the scattering plane of the Molt detector versus azimuthal angle profiles (rotation diagrams) parallel to the original scattering plane (k0, k) one further clarify a lack of rotation symmetry indicated measures P~. The component I',, is analysed, if the two by earlier results on the normal component of polarscattering planes are perpendicular to each other. ization, which were measured for a slightly different Numerical calculations were performed according diffraction geometry [4], and provide experimental to a relativistic LEED theory [6) with model assumpverification of recent predictions based on symmetry lions as in a recent application to P1(1 11) [4). The arguments [5].effective ion-core potential contains an energyMost of the experimental set-up has been dependent local exchange contribution, the inner potendescribed previously [4].The principle of measuring tial has the real and imaginary parts 12 and 4eV, and the longitudinal spin polari...

Vectorial spin polarization detection in multichannel spin-resolved photoemission spectroscopy using an Ir(001) imaging spin filter

“…Symmetry considerations predict an even behavior A(P n ,ϕ) = A(P n ,−ϕ) [35]. This condition agrees with our experimental results within error limits.…”

Spin polarization in low-energy electron diffraction: Surface analysis of Pt(111)

“…Here a detailed description of the modified set-up is given, which was briefly sketched in ref. [2]. The apparatus (see fig.…”

Experimental study of longitudinal and transverse spin polarization in LEED from platinum (111)

“…8). For the polarization components P~ and Pk the symmetry stays threefold, however, as has already been shown [8,15,26]. As regards only the P~(~0) diagrams of Fig.…”

“…The two polarization components parallel to the scattering plane therefore generally do not vanish owing to multiple scattering. For Pt(lll), for example, it has been shown that the longitudinal component Pk, which is parallel to the momentum of the outgoing beam, may contain information [8]:…”