Electronic structure of NiS$_{1-x}$Se$_x$ across the phase transition
  We report very highly resolved photoemission spectra of NiS(1-x)Se(x) across the so-called metal-insulator transition as a function of temperature as well as 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 possibly due to the opening of gaps along specific directions in the Brillouin zone caused by the antiferromagnetic ordering. 
D. D. Sarma(1), S. R. Krishnakumar(1), Nirmala Chandrasekharan(1), E.   Weschke(2), C. Sch\"u{\ss}ler-Langeheine(2), L. Kili...