Evidence for replicate 5p core levels in photoelectron spectra of Eu metal due to nonconstant kinetic-energy resonant Auger decay

Satellites on the low-binding-energy side of core-level photoelectron emission due to extra 4f screening are a well-known feature in the x-ray photoelectron spectra of valence fluctuation materials and rare-earth metals. A notable exception is Eu metal, where up to now no low-binding-energy satellite has been observed. In this paper we show that in Eu metal the 4d−4f resonance can decay via a resonant Auger decay, which is not a constant kinetic-energy feature due to a rapid change of the strength of 4f screening with excitation energy, establishing a low-binding-energy replica of the 5p core-level photoelectron emission

Optical properties (0.1-25 eV) of Nb-Mo and other Nb-based alloys

The dielectric functions of NbxMo1−x alloys (x=0.2,0.5,0.8) and of Nb with 10-at.% Zr, with 20-at.% V, and with 20-at.% Ta were determined in the 0.1-25 eV energy range. Some of the interband region below 3 eV can be interpreted on the basis of the rigid-band model for Nb-Mo while the large structure at 4-4.5 eV cannot be so interpreted in any of the alloys using existing bands. An examination of all the alloys shows that there probably are distortions of the bands due to strain and potential differences. The transitions beginning at about 9 eV, from the Fermi level to a flat band above, are seen to have delocalized final states. All the alloys show two volume and two surface plasmons like those of Nb and Mo

Evidence for a strong impact of the electron-photon matrix element on angle-resolved photoelectron spectra of layered cuprate compounds

Little is known about the impact of the electron-photon matrix element on angle-resolved photoelectron spectra of layered cuprate compounds. Using the example of the model layered cuprate Sr2CuO2Cl2, we demonstrate that the electron-photon matrix element has a significant influence on energy distribution curves, rendering their interpretation as images of the spectral function nontrivial

Direct Determination of Sizes of Excitations from Optical Measurements on Ion-Implanted GaAs

Using a simple model that describes the decrease of the amplitudes of optical structures in ion-implanted crystals, projected areas of several valence and core excitons in GaAs are determined. The last remnant of crystal-related optical structure vanishes for crystallite areas less than (16Å)2

Optical properties and electronic structures of single crystalline RAl3(R=Sc, Yb, and Lu)

The optical conductivities of single crystals of ScAl3, LuAl3, and YbAl3 were measured by spectroscopic ellipsometry in the energy range of 1.5–5.5 eV. The conductivity spectra of all show peaks between 1.5 and 2.0 eV originating from interband transitions. Two additional peaks around at 2.9 and 4.2 eV are observed for ScAl3, and a weak shoulder is observed around at 2.8 eV for LuAl3. Band structure, density of states, and optical conductivity were calculated using the full-potential linear augmented plane wave method. The calculated conductivity spectrum for ScAl3 shows peaks around at 2.7 and 4.3 eV. The distinctive feature of the optical conductivity for ScAl3 comes from the extraordinary large Sc d unoccupied density of states compared to those of Yb d and Lu d. Oxidation effects on the optical properties of the sample were studied using a three-phase model. The calculated optical conductivity of the clean surface using the three-phase model is larger than that of the oxidized surface

Optical properties of RNi2B2C (R=Y,Tb,Er,Dy)

The optical properties of single crystals of RNi2B2C (R=Y,Tb,Er, and Dy) were measured between 1.7 and 5.2 eV at room temperature using a spectroscopic ellipsometer. The spectra for all compounds are similar and the peak positions appear in a similar energy region. The similarity of the spectra of RNi2B2C (R=Tb,Er,Dy) to that of YNi2B2C indicates that the rare-earth 4f states are not actively involved in the optical transitions

Photoelectron spectra of an Al70Pd21Mn9 quasicrystal and the cubic alloy Al60Pd25Mn15

Photoelectron spectra of a fivefold quasicrystalline alloy Al70Pd21Mn9 and a related cubic alloy Al60Pd25Mn15 reveal two noteworthy features. The first is that the Pd 3dlines fall at binding energies which are 2.2 eV higher than in pure Pd. A similar shift is observed for Pd in other alloys. The second noteworthy feature is that the Mn 2p3/2 line is very sharp in the quasicrystal. Fitting the experimental peaks with a Doniach-Sunjic line shpae suggests that the position and density of Mn states near EFis very sensitive to the structural and/or chemical environment of Mn in the alloys, and that this accounts for the shape of the 2p3/2 Mn line. The sharpness of the Mn line may be a fingerprint of the quasicrystalline phase within the AlPdMn family

Ellipsometric and Kerr-effect studies of Pt3−X (X=Mn,Co)

The conductivity tensor of polycrystalline Pt3X (X=Mn,Co) was determined between 1.6 and 5.2 eV. Samples were arc melted, mechanically polished, and annealed at 500°C for 1 h in Ar. The complex dielectric function was measured from 1.3 to 5.2 eV at room temperature with a rotating analyzer ellipsometer. The magneto-optic Kerr effect was studied between 10 and 293 K in magnetic fields up to 3 T. We used the tight-binding linear-muffin-tin-orbital method in the local spin-density approximation to determine the band structure, density of states, and optical conductivity. Including an empirical quasiparticle self-energy and a lifetime broadening yields good agreement of experimental and calculated spectra

Electron-Core-Hole Interaction in GaAsP

The electron-core-hole interaction is studied via energy derivative reflectance spectra of 20-eV transitions from Ga 3dcore levels to lower conduction-band final states in GaAs1−xPx alloys. A two-level anticrossing behavior of line shapes and threshold energies as the relative positions of the L and X minima invert yields a previously unanticipated L−Xmixing energy |VLX|∼50 meV