Two-dimensional stoichiometric boron carbides with unexpected chemical bonding and promising electronic properties

Abstract

We identify two B–C bonding patterns: pyramidal-geometry tetra-coordinated and hexa-coordinated sp²carbon moiety; B₄C₃has an ultrahigh Young's modulus that can even outperform graphene; the B₂C sheet is metallic with a relatively high superconducting transition temperature (<italic>T</italic>_c≈ 21.20 K).