Quantum Phase Transitions in the One-Dimensional S=1 Spin-Orbital Model: Implications for Cubic Vanadates

TL;DR

This paper studies quantum phase transitions in a one-dimensional S=1 spin-orbital model relevant to cubic vanadates, revealing first-order transitions driven by Hund's coupling and magnetic field, with implications for YVO$_3$.

Contribution

It provides a detailed analysis of phase transitions in the model using DMRG, including effects of lattice interactions, which advances understanding of vanadate materials.

Findings

Magnetization jumps at critical magnetic fields indicating first-order transitions.

First-order phase transition driven by Hund's coupling.

Lattice-induced orbital interactions modify the phase diagram.

Abstract

We investigate ground-state properties and quantum phase transitions in the one-dimensional S=1 spin-orbital model relevant to cubic vanadates. Using the density matrix renormalization group, we compute the ground-state energy, the magnetization and the correlation functions for different values of the Hund's coupling $J_H$ and the external magnetic field. It is found that the magnetization jumps at a certain critical field, which is a hallmark of the field-induced first-order phase transition. The phase transition driven by $J_H$ is also of first order. We also consider how the lattice-induced ferro-type interaction between orbitals modifies the phase diagram, and discuss the results in a context of the first-order phase transition observed in YVO$_3$ at 77K.