Doping-driven Mott transition in La1-xSrxTiO3 via simultaneous electron and hole doping of t2g subbands as predicted by LDA plus DMFT calculations

The insulator to metal transition in LaTiO3 induced by La substitution via Sr is studied within multiband exact diagonalization dynamical mean field theory at finite temperatures. It is shown that weak hole doping triggers a large interorbital charge transfer, with simultaneous electron and hole doping of t(2g) subbands. The transition is first order and exhibits phase separation between insulator and metal. In the metallic phase, subband compressibilities become very large and have opposite signs. Electron doping gives rise to an interorbital charge flow in the same direction as hole doping. These results can be understood in terms of a strong orbital depolarization.