Two-Dimensional Magnetic Boron

TL;DR

This paper predicts a novel two-dimensional antiferromagnetic boron material composed of B20 clusters, exhibiting unique flat-band-induced magnetism, and is the first of its kind in elemental boron systems.

Contribution

It introduces the first cluster-based 2D magnetic material in elemental boron, discovered through ab initio evolutionary methods.

Findings

M-boron is thermodynamically metastable.

It exhibits antiferromagnetic order.

The magnetism is due to flat bands from unpaired electrons.

Abstract

We predict a two-dimensional (2D) antiferromagnetic (AFM) boron (designated as M-boron) by using ab initio evolutionary methodology. M-boron is entirely composed of B20 clusters in a hexagonal arrangement. Most strikingly, the highest valence band of M-boron is isolated, strongly localized, and quite flat, which induces spin polarization on each cap of the B20 cluster. This flat band originates from the unpaired electrons of the capping atoms, and is responsible for magnetism. M-boron is thermodynamically metastable and is the first cluster-based 2D magnetic material in the elemental boron system.