Exploring Boron Flatland
Alice in Boron Flatland
In an article just published in Nano Lett., we evaluate the structural stability and diversity of elemental boron layers by treating them as pseudoalloy B1–x⬡x, where ⬡ is a vacancy in the close-packed triangular B lattice. This approach allows for an elegant use of the cluster expansion method in combination with first-principles density-functional theory calculations, leading to a thorough exploration of the configurational space. A finite range of compositions x is found where the ground-state energy is essentially independent of x, uncovering a variety of stable B-layer phases (all metallic) and suggesting polymorphism, in stark contrast to graphene or hexagonal BN.