Electronic Structure of Nis 1−x Se X Typeset Using Revt E X 1

We investigate the electronic structure of the metallic NiS1−xSex 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 manybody multi-band model is found to be successful in describing the Ni 2p core level and valence band, within the same model. The asymmetric line shape as well as the weak intensity feature in the Ni 2p 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. PACS Numbers: 79.60.Bm, 71.28.+d, 71.30.+h, 71.45.Gm Typeset using REVTEX