High efficiency apparatus for spin polarized inverse photoemission

Spin polarized inverse photoemission is a powerful but demanding technique for investigating the interplay between surface magnetism and the spin polarized electronic structure of unoccupied states. We have developed a compact apparatus five times more efficient than similar existing systems, with a sizable reduction of the acquisition time. It consists of an electron source based on a negative electron affinity GaAs photocathode coupled to an appropriate transport electron optics and a bandpass photon detector at fixed energy (9.3 eV) employing a KBr photocathode and a SrF2 window. The detector is placed all around the electron gun, thus providing a sizable increase of the solid collection angle for photons. For calibration and as examples of application, spin integrated/resolved spectra from Ag(001)/Fe(001)-p(1x1)O surfaces are reported. (C) 2004 American Institute of Physics.