Emergent ferromagnetism with Fermi-liquid behavior in proton intercalated CaRuO3

TL;DR

This study demonstrates a reversible transition from non-Fermi-liquid to Fermi-liquid behavior in CaRuO3 induced by protonation, leading to emergent ferromagnetism, and highlights hydrogen's role in electronic and magnetic phase changes.

Contribution

It reveals a novel protonation-induced electronic and magnetic phase transition in CaRuO3, advancing understanding of correlated electron systems and phase control in perovskite ruthenates.

Findings

Protonation induces a crossover from non-Fermi-liquid to Fermi-liquid state.

Emergence of ferromagnetism from a paramagnetic state.

Hydrogen incorporation influences electronic and magnetic phases.

Abstract

The evolution between Fermi liquid and non-Fermi-liquid states in correlated electron systems has been a central subject in condensed matter physics because of the coupled intriguing magnetic and electronic states. An effective pathway to explore the nature of non-Fermi liquid behavior is to approach its phase boundary. Here we report a crossover from non-Fermi liquid to Fermi-liquid state in metallic CaRuO3 through ionic liquid gating induced protonation with electric field. This electronic transition subsequently triggers a reversible magnetic transition with the emergence of an exotic ferromagnetic state from this paramagnetic compound. Our theoretical analysis reveals that hydrogen incorporation plays a critical role in both the electronic and magnetic phase transitions via structural distortion and electron doping. These observations not only help understand the correlated magnetic and electronic transitions in perovskite ruthenate systems, but also provide novel pathways to design electronic phases in correlated materials.