Control of Correlations in Sr4V2O6Fe2As2 by Chemical Stoichiometry

TL;DR

This study investigates how synthesis conditions influence the superconducting and magnetic properties of Sr4V2O6Fe2As2, demonstrating that chemical stoichiometry control can tune electronic correlations and magnetic states.

Contribution

It provides a comprehensive analysis combining experimental and theoretical methods to show how synthesis parameters affect the electronic and magnetic phases of Sr4V2O6Fe2As2.

Findings

Superconductivity depends on synthesis heating profiles.

Vanadium electrons can be tuned from itinerant to insulating states.

Chemical doping influences magnetic and electronic correlations.

Abstract

We show using a combination of powder X-ray and neutron diffraction, first principles calculations, temperature- and field-dependent magnetization, heat capacity and resistivity data that the superconducting behavior of `Sr$_4$V$_2$O$_6$Fe$_2$As$_2$' is dependent on synthesis conditions, particularly, heating profiles result in unintentional chemical doping. This compound can be tuned from a state in which the vanadium electrons are itinerant with a high electronic density of states, to a state where the vanadium-oxide layers are insulating and presumably antiferromagnetic.