Towards Mott design by $\delta$-doping of strongly correlated titanates

TL;DR

This study explores how delta-doping LaTiO3 and GdTiO3 with SrO layers influences their electronic and magnetic properties, revealing layer-dependent metal-insulator transitions and complex magnetic coupling in strongly correlated titanates.

Contribution

It provides a detailed theoretical analysis of delta-doped titanates using advanced computational methods, uncovering novel layer-specific electronic and magnetic phenomena.

Findings

Layer- and temperature-dependent metal-insulator transitions.

Orbital-selective metallic interface dissolves into an orbital-ordered insulator.

Ferromagnetic and antiferromagnetic layer coupling in doped GdTiO3.

Abstract

Doping the distorted-perovskite Mott insulators LaTiO$_3$ and GdTiO$_3$ with a single SrO layer along the [001] direction gives rise to a rich correlated electronic structure. A realistic superlattice study by means of the charge self-consistent combination of density functional theory with dynamical mean-field theory reveals layer- and temperature-dependent multi-orbital metal-insulator transitions. An orbital-selective metallic layer at the interface dissolves via an orbital-polarized doped-Mott state into an orbital-ordered insulating regime beyond the two conducting TiO$_2$ layers. We find large differences in the scattering behavior within the latter. Breaking the spin symmetry in $\delta$-doped GdTiO$_3$ results in blocks of ferromagnetic itinerant and ferromagnetic Mott-insulating layers which are coupled antiferromagnetically.