Incommensurate Magnetic Order in Hole-Doped Infinite-layer Nickelate Superconductors

TL;DR

This study uses first-principles and spin-wave theory calculations to explore magnetic order in hole-doped nickelate superconductors, revealing incommensurate magnetic states and their relation to doping and magnetic interactions.

Contribution

It uncovers the incommensurate magnetic order in hole-doped nickelates and links magnetic interactions with doping, advancing understanding of their magnetic properties.

Findings

NdNiO$_2$ is near a transition between 2D AFM and 3D C-AFM states.

Hole doping stabilizes an incommensurate spin state with a continuously increasing wave vector.

Competition between first- and third-neighbor magnetic interactions drives incommensurate magnetic order.

Abstract

Magnetism and superconductivity are closely entangled, elucidating the magnetic interactions in nickelate superconductors is at the heart of understanding the pairing mechanism. Our first-principles and spin-wave theory calculations highlight that NdNiO$_2$ is in the vicinity of a transition between a quasi-two-dimensional (2D) antiferromagnetic (AFM) state and a three-dimensional (3D) C-AFM state. Both states could accurately reproduce the experimentally measured magnetic excitation spectra, which was previously explained in terms of a 2D model. We further reveal that hole doping stabilizes an incommensurate (IC) spin state and the IC wave vector increases continuously. Direct links between hole doping, magnetization, exchange constants, and magnetic order are established, revealing that the competition between first-neighbor and third-neighbor in-plane magnetic interactions is the key for the IC magnetic order.