Determination of the orbital moment and crystal field splitting in LaTiO$_{3}$

TL;DR

This study uses advanced spectroscopic techniques to measure the orbital moment and crystal field splitting in LaTiO₃, revealing a reduced orbital moment and significant crystal field splitting that challenges the orbital liquid hypothesis.

Contribution

It provides the first direct measurement of the orbital moment and crystal field splitting in LaTiO₃ using spin-resolved photoelectron spectroscopy and x-ray absorption spectroscopy.

Findings

Orbital moment in LaTiO₃ is strongly reduced both below and above the Néel temperature.

Crystal field splitting in the t₂g subshell is approximately 0.12-0.30 eV.

Large crystal field splitting does not support the formation of an orbital liquid.

Abstract

Utilizing a sum-rule in a spin-resolved photoelectron spectroscopic experiment with circularly polarized light, we show that the orbital moment in LaTiO$_3$ is strongly reduced both below and above the N\'{e}el temperature. Using Ti $L_{2,3}$ x-ray absorption spectroscopy as a local probe, we found that the crystal field splitting in the $t_{2g}$ subshell is about 0.12-0.30 eV. This large splitting does not facilitate the formation of an orbital liquid.