Formation of orbital-selective electron states in LaTiO$_3$/SrTiO$_3$ superlattices

TL;DR

This study uses advanced computational methods to explore how electron states become orbital-selective at the interfaces of LaTiO3/SrTiO3 superlattices, revealing complex multiorbital electronic structures influenced by strong correlations.

Contribution

It presents a combined LDA+DMFT approach with pseudopotentials and quantum Monte Carlo to analyze orbital-selective states in LaTiO3/SrTiO3 superlattices, including structural relaxations.

Findings

Identification of Ti(3d_{xy}) dominated quasiparticle peaks

Observation of lower Hubbard bands consistent with photoemission

Correlation effects near band-insulating and Mott-insulating limits

Abstract

The interface electronic structure of correlated LaTiO$_3$/SrTiO$_3$ superlattices is investigated by means of the charge self-consistent combination of the local density approximation (LDA) to density functional theory (DFT) with dynamical mean-field theory (DMFT). Utilizing a pseudopotential technique together with a continuous-time quantum Monte-Carlo approach, the resulting complex multiorbital electronic states are addressed in a coherent fashion beyond static mean-field. General structural relaxations are taken into account on the LDA level and cooperate with the driving forces from strong electronic correlations. This alliance leads to an Ti($3d_{xy}$) dominated low-energy quasiparticle peak and a lower Hubbard band in line with photoemission studies. Furthermore correlation effects close to the band-insulating bulk SrTiO$_3$ limit as well as the Mott-insulating bulk LaTiO$_3$ limit are studied via realistic single-layer embeddings.