One-Dimensional Confinement and Enhanced Jahn-Teller Instability in LaVO$_3$

TL;DR

This paper investigates how one-dimensional confinement influences orbital ordering and Jahn-Teller instability in LaVO$_3$, revealing enhanced lattice distortions and explaining experimental optical spectra and transition temperature proximity.

Contribution

It demonstrates that anisotropic orbital interactions significantly enhance Jahn-Teller instability in LaVO$_3$, providing a theoretical explanation for experimental observations.

Findings

Strong one-dimensional anisotropy in orbital interactions.

Enhanced Jahn-Teller instability due to anisotropy.

Consistency with experimental optical spectra and transition temperatures.

Abstract

Ordering and quantum fluctuations of orbital degrees of freedom are studied theoretically for LaVO$_3$ in spin-C-type antiferromagnetic state. The effective Hamiltonian for the orbital pseudospin shows strong one-dimensional anisotropy due to the negative interference among various exchange processes. This significantly enhances the instability toward lattice distortions for the realistic estimate of the Jahn-Teller coupling by first-principle LDA+$U$ calculations, instead of favoring the orbital singlet formation. This explains well the experimental results on the anisotropic optical spectra as well as the proximity of the two transition temperatures for spin and orbital orderings.