Dirac cones in Two-dimensional Borane

TL;DR

This paper introduces two-dimensional borane, a novel semimetallic material with Dirac cones at the Fermi level, exhibiting near-ideal linear dispersion and potential for synthesis under high pressure.

Contribution

The study predicts the electronic structure of 2D borane with Dirac cones using DFT, highlighting its unique properties and proposing a synthesis route.

Findings

2D borane is semimetallic with Dirac cones at the Fermi level.

The Dirac cones have lower curvature than graphene, indicating near-ideal linear dispersion.

High-pressure conditions may enable synthesis of 2D borane.

Abstract

We introduce two-dimensional borane, a single-layered material of BH stoichiometry, with promising electronic properties. We show that, according to Density Functional Theory calculations, two-dimensional borane is semimetallic, with two symmetry-related Dirac cones meeting right at the Fermi energy $E_f$. The curvature of the cones is lower than in graphene, thus closer to the ideal linear dispersion. Its structure, formed by a puckered trigonal boron network with hydrogen atoms connected to each boron atom, can be understood as distorted, hydrogenated borophene (Science \textbf{350}, 1513 (2015)). Chemical bonding analysis reveals the boron layer in the network being bound by delocalized four-center two-electron ${\sigma}$ bonds. Finally, we suggest high-pressure could be a feasible route to synthesise two-dimensional borane.