Nature of itineracy in CoV$_2$O$_4$: A first principles study

TL;DR

This study uses first principles calculations to explore the pressure-induced insulator-to-metal transition in CoV$_2$O$_4$, proposing that localized and itinerant electrons play a key role, with the latter scenario aligning better with experiments.

Contribution

It introduces a comparative analysis of two mechanisms for metallicity in CoV$_2$O$_4$, emphasizing the role of localized and itinerant electrons over spin-orbit interactions.

Findings

Pressure induces metallicity in CoV$_2$O$_4$

Localized and itinerant electrons explain the transition

Second scenario aligns better with experiments

Abstract

Inspired by recent experiments, we have theoretically explored the nature of itineracy in CoV$_2$O$_4$ under pressure and investigated, using first principles density functional theory calculations, if it has any magnetic and orbital ordering. Our calculations indicate that there could be two possible routes to obtain the experimentally observed pressure induced metallicity in this system. One is the spin-orbit interaction coupled with Coulomb correlation which can take the system from a semiconducting state at ambient pressure to a metallic state under high pressure. The other mechanism, as indicated by our GGA+U calculations, is based on the presence of two types of electrons in the system: localized and itinerant. An effective Falicov-Kimball model could then possibly explain the observed insulator to metal transition. Comparison of the two scenarios with existing experimental observations leads us to believe that the second scenario offers a better explanation for the mechanism of insulator to metal transition in CoV$_2$O$_4$ under pressure.