Metallizing the Mott insulator TiOCl by electron doping: a view from LDA+DMFT

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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, co-incident, 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.