Quantum Magnetic Properties in Perovskite with Anderson Localized Artificial Spin-1/2

TL;DR

This study demonstrates that controlled chemical disorder in a perovskite material can induce quantum magnetic properties similar to spin liquids, through localized artificial spin-1/2 dimers exhibiting fractionalization and excitation phenomena.

Contribution

It introduces a novel approach to realize quantum magnetic states in perovskites via Anderson localization of impurity spins, expanding the potential for quantum materials research.

Findings

Artificial spin-1/2 dimers form due to Co impurity localization.

Low-temperature singlet-to-triplet excitations observed.

High-temperature fractionalized spin continuum detected.

Abstract

Quantum magnetic properties in a geometrically frustrated lattice of spin-1/2 magnet, such as quantum spin liquid or solid and the associated spin fractionalization, are considered key in developing a new phase of matter. The feasibility of observing the quantum magnetic properties, usually found in geometrically frustrated lattice of spin-1/2 magnet, in a perovskite material with controlled disorder is demonstrated. It is found that the controlled chemical disorder, due to the chemical substitution of Ru ions by Co-ions, in a simple perovskite CaRuO3 creates a random prototype configuration of artificial spin-1/2 that forms dimer pairs between the nearest and further away ions. The localization of the Co impurity in the Ru matrix is analyzed using the Anderson localization formulation. The dimers of artificial spin-1/2, due to the localization of Co impurities, exhibit singlet-to-triplet excitation at low temperature without any ordered spin correlation. The localized gapped excitation evolves into a gapless quasi-continuum as dimer pairs break and create freely fluctuating fractionalized spins at high temperature. Together, these properties hint at a new quantum magnetic state with strong resemblance to the resonance valence bond system.