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Register a new userX-ray photoemission study of NiS_{2-x}Se_x (x = 0.0 - 1.2)
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Added by
Krishnakumar S. R. Menon
Publication date
2003
fields
Physics
and research's language is
English
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Electronic structure of NiS_{2-x}Se_x system has been investigated for various compositions (x) using x-ray photoemission spectroscopy. An analysis of the core level as well as the valence band spectra of NiS_2 in conjunction with many-body cluster calculations provides a quantitative description of the electronic structure of this compound. With increasing Se content, the on-site Coulomb correlation strength (U) does not change, while the band width W of the system increases, driving the system from a covalent insulating state to a pd-metallic state.
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We investigate the electronic structure of the metallic NiS$_{1-x}$Se$_x$ system using various electron spectroscopic techniques. The band structure results do not describe the details of the spectral features in the experimental spectrum, even for this paramagnetic metallic phase. However, a parameterized many-body multi-band model is found to be successful in describing the Ni~2$p$ core level and valence band, within the same model. The asymmetric line shape as well as the weak intensity feature in the Ni~2$p$ core level spectrum has been ascribed to extrinsic loss processes in the system. The presence of satellite features in the valence band spectrum shows the existence of the lower Hubbard band, deep inside the $pd$ metallic regime, consistent with the predictions of the dynamical mean field theory.
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