Metallizing the Mott insulator TiOCl by electron doping

Based on recent experiments, we describe the Mott insulating, but undimerized, state of TiOCl using the local-density approximation combined with multi-orbital dynamical mean field theory (LDA+DMFT) for this 3d1 system. Good agreement with the high estimated value of the superexchange is obtained. The possibility of an electron-doped insulator–metal transition in TiOCl is investigated in this scheme and a Mott–Hubbard transition with a jump in carrier density inside the metallic state is found. Clear, coincident, discontinuous changes in orbital occupations are observed, showing that such a transition would involve strong, multi-orbital correlations. These results call for studies on suitably intercalated TiOCl that may induce metallization and, possibly, unconventional superconductivity.