SPIN-RESOLVED AND ANGLE-RESOLVED PHOTOEMISSION-STUDY OF CHEMISORBED P(1X1) O ON EPITAXIAL ULTRATHIN FE/W(001) FILMS

Chemisorbed p(1 x 1) oxygen on ultrathin epitaxial Fe films grown on W(001) are studied using spin-and angle-resolved photoemission. In agreement with theoretical predictions, single-monolayer (ML) Fe films on W(001) are found to be nonmagnetic; 2-ML-thick Fe films are magnetic, and chemisorbed p(1 x 1) oxygen does not destroy the magnetism. Even- and odd-symmetry oxygen 2p-derived bands are measured along the GAMMABAR-XBAR and GAMMABAR-MBAR directions of the two-dimensional Brillouin zone. Oxygen-derived features in the photoemission spectra exhibit magnetic exchange splitting as well as spin-dependent intrinsic linewidths that are governed by lifetime effects and initial-state mixing with Fe bands. Oxygen 2p-band narrowing resulting from the expanded Fe thin-film lattice constant is observed. The results are compared with relevant calculations and corresponding experimental studies of p(1 x 1) oxygen on bulk Fe(001) surfaces.