Magnetic Ni-N-Ni Centers in N-substituted NiO

TL;DR

This study investigates how substituting nitrogen for oxygen in NiO creates Ni-N-Ni magnetic centers, altering local electronic states and magnetic interactions, with potential applications in quantum technologies.

Contribution

It reveals the formation of Ni-N-Ni centers in N-substituted NiO and demonstrates their properties using theoretical and experimental methods.

Findings

Formation of Ni-N-Ni centers with five spins

Modification of local magnetic moments by nitrogen substitution

Potential for quantum technology applications

Abstract

To explore how anion substitution modifies the existing magnetism in strongly correlated oxides, we investigate local electronic states and magnetic ordering in nickel oxide (NiO) induced by substituting oxygen (O) with nitrogen (N). Each N introduces an additional N 2p hole and modifies the magnetic moment of a neighboring nickel (Ni) cation site, as the exchange interaction between this hole and the Ni eg electrons exceeds the Ni-O-Ni superexchange interaction. This leads to the formation of Ni-N-Ni centers consisting of five spins, without perturbing the antiferromagnetic NiO lattice. These centers are studied using density functional theory and confirmed through high-resolution spectroscopy on N-substituted NiO thin films grown by molecular beam epitaxy. This type of magnetic design may enable future advances in quantum technologies based on strongly correlated materials, such as quantum sensors and spin-based qubits.