Electronic structure ofRAuMgandRAgMg(R=Eu,

J. Gegner

¹

,

T. C. Koethe

²

,

Hua Wu

³

et al.

Abstract

We have investigated the electronic structure of the equiatomic EuAuMg, GdAuMg, YbAuMg and GdAgMg intermetallics using x-ray photoelectron spectroscopy. The spectra revealed that the Yb and Eu are divalent while the Gd is trivalent. The spectral weight in the vicinity of the Fermi level is dominated by the mix of Mg s, Au/Ag sp and RE spd bands, and not by the RE 4f . We also found that the Au and Ag d bands are extraordinarily narrow, as if the noble metal atoms were impurities submerged in a low density sp metal host. The experimental results were compared with band structure calculations, and we found good agreement provided that the spin-orbit interaction in the Au an Ag d bands is included and correlation effects in an open 4f shell are accounted for using the local density approximation + Hubbard U scheme. Nevertheless, limitations of such a mean-field scheme to explain excitation spectra are also evident.

Electronic structure ofSrPt4Ge12: Combined photoelectron spectroscopy and band structure study

“…Remarkable is that the SrPt 4 Ge 12 4f peaks are shifted by 1 eV to higher binding energies in comparison to those of Pt metal. Similar shifts have also been observed in other noble metal intermetallic compounds, 23,24,25 indicating a more dilute electron density around the noble metal sites. To compare this chemical shift to LDA calculations, one has to take into account that LDA does not incorporate many body effects of the final state, manifesting in the asymmetric line shape of the spectra as we will discuss below in more detail.…”

“…We would like to note that the main peak of the calculated Pt 5d DOS is positioned at a some- what lower binding energy than that of the experimental difference spectrum. Similar small deviations have been observed in other intermetallic materials 23,24 and can be attributed to the inherent limitations of mean-field methods like the LDA to calculate the dynamic response of a system. Figure 5 shows the difference of the spectrum taken at 190 eV and the rescaled spectrum at 700 eV.…”

Rare earth–transition metal–magnesium compounds—An overview

“…The electronic structures of REAuMg and REAgMg (RE ¼ Eu, Gd, Yb) have been determined experimentally through X-ray photoelectron spectroscopy [78]. The spectra clearly confirm the divalent character of europium and ytterbium and the trivalent character of gadolinium.…”

Electronic structure ofRAuSn(R=Sc, Ce, Gd, Er, and Lu) investigated with x-ray photoelectron spectroscopy and band structure calculati

“…The spectra of all compounds have in common that they show a doublet structure between 4 and 7 eV binding energies. Using the results from a previous study on the RAuMg system, 21 we can assign this doublet structure to the Au 5d levels, split up by the spin-orbit interaction. For GdAuSn, ErAuSn, and LuAuSn, the contribution of the rare-earth 4f orbitals is clearly visible.…”