Predicting Two-Dimensional Boron-Carbon Compounds by the Global Optimization Method

TL;DR

This paper uses a particle-swarm optimization method to predict stable two-dimensional boron-carbon structures, revealing their metallic or semiconducting nature, structural motifs, and high thermal stability across various compositions.

Contribution

It introduces a global optimization approach to systematically predict and analyze 2D B-C compounds, identifying new stable structures and their electronic properties.

Findings

Most 2D B-C compounds are metallic, except BC3 which is semiconducting.

C-rich B-C structures resemble boron-doped graphene with zigzag chains.

B-rich B-C structures feature a novel planar-tetracoordinate carbon motif.

Abstract

We adopt a global optimization method to predict two-dimensional (2D) nanostructures through the particle-swarm optimization (PSO) algorithm. By performing PSO simulations, we predict new stable structures of 2D boron-carbon (B-C) compounds for a wide range of boron concentrations. Our calculations show that: (1) All 2D B-C compounds are metallic except for BC3 which is a magic case where the isolation of carbon six-membered ring by boron atoms results in a semiconducting behavior. (2) For C-rich B-C compounds, the most stable 2D structures can be viewed as boron doped graphene structures, where boron atoms typically form 1D zigzag chains except for BC3 in which boron atoms are uniformly distributed. (3) The most stable 2D structure of BC has alternative carbon and boron ribbons with strong in-between B-C bonds, which possesses a high thermal stability above 2000K. (4) For B-rich 2D B-C compounds, there is a novel planar-tetracoordinate carbon motif with an approximate C2v symmetry.