Measurement of collective excitations in VO$_2$ by resonant inelastic X-ray scattering

TL;DR

This study uses resonant inelastic X-ray scattering to investigate the excitation spectrum of VO₂, revealing how charge, spin, and lattice excitations evolve across the metal-insulator transition, including a potential singlet-triplet dimer excitation.

Contribution

First application of RIXS to probe collective excitations in VO₂ across its metal-insulator transition, highlighting the evolution of spin, charge, and lattice dynamics.

Findings

Identification of a low-temperature singlet-triplet excitation candidate.

Observation of spectral changes across the metal-insulator transition.

Insights into the interplay of electron correlations and lattice effects.

Abstract

Vanadium dioxide is of broad interest as a spin-1/2 electron system that realizes a metal-insulator transition near room temperature, due to a combination of strongly correlated and itinerant electron physics. Here, resonant inelastic X-ray scattering is used to measure the excitation spectrum of charge, spin, and lattice degrees of freedom at the vanadium L-edge under different polarization and temperature conditions. These spectra reveal the evolution of energetics across the metal-insulator transition, including the low temperature appearance of a strong candidate for the singlet-triplet excitation of a vanadium dimer.