Spin-polarized resonant surface state in (1 1 1) Sm1−x Gd x Al2, a zero-magnetization ferromagnet

The electronic structure of (1 1 1) Sm1−x Gd x Al2, a zero-magnetization ferromagnet, is investigated by angle- and spin- resolved photoemission spectroscopy. An intense electron pocket strongly localized around and close to the Fermi level is observed and analyzed in detail. Its various characteristics, combined with electronic structure calculations, reveal a resonant surface state of 5d character and Λ1 symmetry, likely built on bulk states developing around L points. It exhibits moreover a low temperature positive spin polarization at the Fermi level, of strong interest for spin-dependent transport properties in Sm1−x Gd x Al2-based spintronic devices.