5f-electron localization in PuSe and PuSb

Thin layers of PuSb and PuSe were studied by photoelectron spectroscopy. X- ray photoelectron spectroscopy and high-resolution valence-band ultraviolet photoelectron spectroscopy spectra show localization of the 5f states and a low density of states at EF in PuSb. In PuSe, which can be classified as a heavy fermion system with low carrier density, we observed three narrow p eaks in the valence band, which can be related to the 5f emission. These th ree features are very sensitive to stoichiometry deviations and disappear f or PuSe prepared at T = 77 K.