Correlated vs. conventional insulating behavior in the Jeff=1/2 vs. 3/2   bands in the layered iridate Ba2IrO4
  We employ molecular beam epitaxy to stabilize Ba2IrO4 thin films and utilize in situ angle-resolved photoemission spectroscopy to investigate the evolution of its electronic structure through the Neel temperature TN. Our measurements indicate that dispersions of the relativistic Jeff=1/2 and 3/2 bands exhibit an unusual dichotomy in their behavior through the Neel transition. Although the charge gap survives into the paramagnetic state, only the Jeff=1/2 state exhibits a strong temperature dependence and its gap softens with increasing temperature approaching TN, while the nearly fully occupied Jeff=3/2 state which remains nearby in energy exhibits negligible changes with temperature. 
M. Uchida, Y. F. Nie, P. D. C. King, C. H. Kim, C. J. Fennie, D. G.   Schlom, and K. M. Shen
cond-mat.str-el cond-mat.mtrl-sci