Ground state tuning of the metal-insulator transition by compositional variations in BaIr1-xRuxO3(0<x<1)

TL;DR

This study explores how substituting Ru for Ir in BaIrO3 tunes the material's transition from insulator to metal by altering spin-orbit interactions and structural distortions, revealing a complex phase diagram.

Contribution

It demonstrates how compositional variations in BaIr1-xRuxO3 modulate spin-orbit coupling and structural effects, leading to diverse magnetic and electronic phases.

Findings

Light Ru doping causes drops in magnetic order and resistivity, with a crossover from metallic to insulating behavior.

Heavier Ru doping stabilizes a metallic state with strong spin frustration.

The phase diagram is rich, showing transitions driven by compositional tuning.

Abstract

BaIrO3 is a magnetic insulator driven by the spin-orbit interaction (SOI), whereas BaRuO3 is a paramagnet and exhibits a crossover from a metallic to an insulating regime. Our investigation of structural, magnetic, transport and thermal properties reveals that substitution of Ru4+ (4d4) ions for Ir5+ (5d5) ions in BaIrO3 reduces the magnitudes of the SOI and a monoclinic structural distortion, and rebalances the competition between the SOC and the lattice degrees freedom to generate a rich phase diagram for BaIr1-xRuxO3 (0< x <1). There are two major effects of Ru additions: (1) Light Ru doping (0 < x < 0.15) prompts simultaneous, precipitous drops in both the magnetic ordering temperature TN and the electrical resistivity, which exhibits a crossover behavior from a metallic to an insulating state near TN. (2) Heavier Ru doping (0.41< x < 0.9) induces a robust metallic state with a strong spin frustration generated by competing antiferromagnetic and ferromagnetic interactions.