Intertwined magnetic, structural, and electronic transitions in V$_2$O$_3$

TL;DR

This study provides a detailed, multi-technique analysis of the coupled magnetic, structural, and electronic phase transitions in V$_2$O$_3$, revealing phase coexistence and the interplay of degrees of freedom during the transition.

Contribution

It offers a comprehensive, temperature-resolved characterization of phase coexistence and coupling in V$_2$O$_3$ using multiple advanced measurement techniques.

Findings

Stable coexistence of phases over a broad temperature range

Electronic, magnetic, and structural degrees of freedom are tightly coupled

Evidence of antiferromagnetic fluctuations near the transition

Abstract

We present a coordinated study of the paramagnetic-to-antiferromagnetic, rhombohedral-to-monoclinic, and metal-to-insulator transitions in thin-film specimens of the classic Mott insulator V$_2$O$_3$ using low-energy muon spin relaxation, x-ray diffraction, and nanoscale-resolved near-field infrared spectroscopic techniques. The measurements provide a detailed characterization of the thermal evolution of the magnetic, structural, and electronic phase transitions occurring in a wide temperature range, including quantitative measurements of the high- and low-temperature phase fractions for each transition. The results reveal a stable coexistence of the high- and low-temperature phases over a broad temperature range throughout the transition. Careful comparison of temperature dependence of the different measurements, calibrated by the resistance of the sample, demonstrates that the electronic, magnetic, and structural degrees of freedom remain tightly coupled to each other during the transition process. We also find evidence for antiferromagnetic fluctuations in the vicinity of the phase transition, highlighting the important role of the magnetic degree of freedom in the metal-insulator transition.