Electronic structure of$ NiS_{1-x}Se_x$ across the phase transition

We report very highly resolved photoemission spectra of NiS1-xSex across the so-called metal-insulator transition as a function of temperature as well ss composition. The present results convincingly demonstrate that the low temperature, antiferromagnetic phase is metallic, with a reduced density of states at E-F. This decrease is due possibly to the opening of gaps along specific directions in the Brillouin zone caused by the antiferromagnetic ordering