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From the first principles calculation based on the density functional theory, we find that consideration of electron–electron correlation drives Fe2CrSn from a barely half-metallic state to a magnetic semiconductor. However, in both cases, the magnetic state remains ferrimagnetic with a total spin moment of 2 μ B , with Cr carrying a large local moment that is oppositely aligned to that of Fe.

We present a comparative study of the near fermi-level electronic structure of single crystal and highly oriented pyrolytic graphite (HOPG). Angle resolved photoelectron spectroscopy and angle resolved inverse photoelectron spectroscopy have been used to probe the occupied and unoccupied electronic states, respectively. The band dispersions showed by single crystal graphite along its Γ K and Γ M symmetry directions were found to be in agreement with calculated band structure of graphite. The π bands of single crystal graphite were found to have a splitting of ∼ 0.5 eV at the K-point. We also observe the presence of a quasiparticle peak below EF at the K point at low temperature which indicates a strong electron–phonon coupling in graphite. In HOPG, the M and K points like features were found to be present in the same radial direction due to the superposition of the Γ M and Γ K directions. Results from our angle resolved inverse photoemission spectroscopy present the dispersion of the conduction band states, particularly the lower π ⁎ band. We have also found the presence of some non-dispersive features in both the valence and the conduction bands.

Zinc oxide (ZnO) thin films have been deposited with various substrate temperatures by spray pyrolysis technique onto glass substrates. X-ray diffraction (XRD) results showed the random growth orientation of the crystallites and the presence of the wurtzite phase of ZnO. The x-ray photoelectron spectroscopy (XPS) measurements reveal the presence of Zn 2+ and chemisorbed oxygen in ZnO thin films. Atomic force micrograms (AFM) revealed a granular, polycrystalline morphology for the films. The grain size is found to increase as the substrate temperature increases. All films exhibit a transmittance of about 85% in the visible region. The photoluminescence (PL) measurements indicated that the intensity of emission peaks significantly varying with substrate temperature. Electrical resistivity has been found to decrease; while the carrier concentration increases with substrate temperature.

We have studied the occupied and unoccupied electron states of the Pr 1 - x Ca x MnO 3 ( x = 0.2 , 0.33 and 0.4) near the Fermi level across their ferromagnetic–antiferromagnetic phase boundary using ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy. The photoemission data show that the pseudogap formation in these compounds occur over an energy scale of 0.48 ± 0.02 eV . From a combined analysis of the photoemission and inverse photoemission results, we have estimated the charge transfer energy in these compounds to be ∼ 2.8 ± 0.2 eV . The results have been explained on the basis of the theoretical models that describe the electronic phase separation.

We discuss high-energy spectroscopic results for systems representing electron doping near the d 0 configuration and establish that the spectral evolution with doping is inconsistent with expectations based on the Hubbard model. We argue that this failure arises due to the neglect of disorder in the real system. We present a new theoretical approach which takes into account the inhomogeneity of real systems; this approach provides results which are qualitatively different from the standard homogeneous models, but are in agreement with the experimental observations.