Electron-spin-polarization effects in low-energy electron diffraction, ion neutralization and metastable-atom deexcitation at solid surfaces

This project is directed towards development of new surface-sensitive spectroscopies based on electron-spin dependences in electron-atom- and ion-surface interactions. Spin polarization effects in LEED (i.e., PLEED) can be exploited to provide structural information at crystalline surfaces. During the current contract year, a comprehensive study of nickel (110) has yielded polarization vs. energy profiles that are rich in structure and with surprisingly large peak polarizations (approx. 20%). Addition of an ordered tellurium adlayer significantly changes both the PLEED polarization and intensity profiles. Study of Te/Ni fractional order beams is expected to provide new insight on the potential of PLEED as a new diagnostic with particular sensitivity to adlayer properties. Work has begun on construction of a GaAs spin-polarized electron source that should provide improved accuracy and data acquisition rates in future PLEED experiments