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

TL;DR

This paper uses LDA+DMFT to study the Mott insulator TiOCl, revealing a potential electron-doped insulator-metal transition with strong multi-orbital correlations, suggesting avenues for inducing metallization and superconductivity.

Contribution

It demonstrates the application of LDA+DMFT to TiOCl, predicting a Mott-Hubbard transition with orbital occupation changes, advancing understanding of electron doping effects.

Findings

Prediction of a Mott-Hubbard transition with carrier density jump

Observation of discontinuous orbital occupation changes

Agreement with experimental superexchange values

Abstract

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 $3d^{1}$ 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 {\it 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.