Electronic structure of rare-earth chromium antimonides RECrSb3 (RE=La–Nd, Sm, Gd–Dy, Yb) by X-ray photoelectron spectroscopy

The electronic structure of the ternary rare-earth chromium antimonides RECrSb3 (RE=La–Nd, Sm, Gd–Dy, Yb) has been examined by high-resolution X-ray photoelectron spectroscopy (XPS) for the first time. The RE 3d or 4d core-line spectra are substantially complicated by the presence of satellite peaks but their general resemblance to those of RE2O3 tends to support the presence of trivalent RE atoms in RECrSb3. However, the Yb 4d spectrum of YbCrSb3 also shows peaks that are characteristic of divalent ytterbium. The Cr 2p core-line spectra exhibit asymmetric lineshapes and little change in binding energy (BE) relative to Cr metal, providing strong evidence for electronic delocalization. The Sb 3d core-line spectra reveal slightly negative BE shifts relative to elemental antimony, supporting the presence of anionic Sb species in RECrSb3. The experimental valence band spectrum of LaCrSb3 matches well with the calculated density of states, and it can be fitted to component peaks belonging to individual atoms to yield an average formulation that agrees well with expectations (“La3+Cr3+(Sb2−)3”). On progressing from LaCrSb3 to NdCrSb3, the 4f-band in the valence band spectra grows in intensity and shifts to higher BE. The valence band spectrum for YbCrSb3 also supports the presence of divalent ytterbium. In their valence band spectra, the 4f-band intensifies and shifts to higher BE on progressing from LaCrSb3 to NdCrSb3. [Display omitted] ► High-resolution core-line and valence band XPS spectra were measured for RECrSb3. ► Divalent Yb is present in YbCrSb3, in contrast to trivalent RE in other members. ► Asymmetric Cr 2p spectral lineshape confirms delocalization of Cr valence electrons. ► Small negative Sb 3d BE shifts support assignment of anionic Sb atoms. ► Fitted valence band spectra show shifts in the 4f band as RE is changed.