Novel electronic and magnetic properties of BN sheet decorated with hydrogen and fluorine

TL;DR

This study uses first principles calculations to reveal that hydrogen and fluorine functionalization of BN sheets results in tunable electronic and magnetic properties, differing significantly from similar modifications in graphene, with potential for novel applications.

Contribution

It demonstrates unique electronic and magnetic behaviors of functionalized BN sheets, including tunable band gaps and magnetic states, which are distinct from graphene.

Findings

BN sheet band gap can be tuned from 4.7 eV to 0.6 eV.

Functionalized BN sheets can exhibit ferromagnetic, antiferromagnetic, or degenerate magnetic states.

Magnetic coupling stability can be modulated by external strain.

Abstract

First principles calculations based on density functional theory reveal some unusual properties of BN sheet functionalized with hydrogen and fluorine. These properties differ from those of similarly functionalized graphene even though both share the same honeycomb structure. (1) Unlike graphene which undergoes a metal to insulator transition when fully hydrogenated, the band gap of the BN sheet significantly narrows when fully saturated with hydrogen. Furthermore, the band gap of the BN sheet can be tuned from 4.7 eV to 0.6 eV and the system can be a direct or an indirect semiconductor or even a half-metal depending upon surface coverage. (2) Unlike graphene, BN sheet has hetero-atomic composition, when co-decorated with H and F, it can lead to anisotropic structures with rich electronic and magnetic properties. (3) Unlike graphene, BN sheets can be made ferromagnetic, antiferromagnetic, or magnetically degenerate depending upon how the surface is functionalized. (4) The stability of magnetic coupling of functionalized BN sheet can be further modulated by applying external strain. Our study highlights the potential of functionalized BN sheets for novel applications.