Magnetic Multilayer Edges in Bernal-Stacked Hexagonal Boron Nitride

TL;DR

This paper investigates the magnetic properties of nitrogen-terminated zigzag edges in Bernal-stacked hexagonal boron nitride (AB-hBN), revealing their potential for experimental study and applications in spintronics at low temperatures.

Contribution

It demonstrates that open edges in multilayer AB-hBN remain intact and explores their magnetic interactions using theoretical models and simulations.

Findings

Open edges in multilayer AB-hBN are stable and accessible for experiments.

Edge spins form weakly interacting chains with measurable correlation lengths.

Potential applications in magnetoresistance and spintronics at low temperatures.

Abstract

Single-layer $\it{h}$-BN is known to have edges with unique magnetism, however, in the commonly fabricated multilayer $\text{AA}^{\prime}$-$\it{h}$-BN, edge relaxations occur that create interlayer bonds and eliminate the unpaired electrons at the edge. Recently, a robust method of growing the unconventional Bernal-stacked $\it{h}$-BN (AB-$\it{h}$-BN) has been reported. Here, we use theoretical approaches to investigate the nitrogen-terminated zigzag edges in AB-$\it{h}$-BN that can be formed in a controlled fashion using a high-energy electron beam. We find that these "open" edges remain intact in bilayer and multilayer AB-$\it{h}$-BN, enabling researchers potentially to investigate these edge states experimentally. We also investigate the thermodynamics of the spin configurations at the edge by constructing a lattice model that is based on parameters extracted from a set of first-principles calculations. We find that the edge spins in neighboring layers interact very weakly, resulting in a sequence of independent spin chains in multilayer samples. By solving this model using Monte Carlo simulations, we can determine nm-scale correlation lengths at liquid-N$_{2}$ temperatures and lower. At low temperatures, these edges may be utilized in magnetoresistance and spintronics applications.