Evolution of Spin-Orbital-Lattice Coupling in the $R$VO$_3$ Perovskites

TL;DR

This paper presents a microscopic model explaining the phase diagram of $R$VO$_3$ perovskites, highlighting the complex interplay between superexchange, orbital-lattice coupling, and lattice distortions affecting magnetic and orbital orders.

Contribution

It introduces a detailed microscopic model that elucidates the mechanisms behind phase transitions in $R$VO$_3$ perovskites, accounting for lattice effects and magnon energy variations.

Findings

Lattice strain influences the onset of magnetic and orbital order.

Orbital fluctuations are partially suppressed by lattice distortions.

Magnon energies decrease from LaVO$_3$ to YVO$_3$.

Abstract

We introduce a microscopic model which unravels the physical mechanisms responsible for the observed phase diagram of the $R$VO$_3$ perovskites. It reveals a nontrivial interplay between superexchange, the orbital-lattice coupling due to the GdFeO$_3$-like rotations of the VO$_6$ octahedra, and orthorhombic lattice distortions. We find that the lattice strain affects the onset of the magnetic and orbital order by partial suppression of orbital fluctuations. The present approach provides also a natural explanation of the observed reduction of magnon energies from LaVO$_3$ to YVO$_3$.