  This work describes the implementation of a genetic algorithm-based strategy
combined with first-principles computations for identifying the structure of
the most stable boron 1D structures. We focus our attention on the structure of
ultrathin 1D boron structures given the lack of previous experimental and
theoretical work on this topic. Our methodology yields reasonable structural
candidates for further optimizations at the DFT level with tighter convergence
criteria. The simulations involved 1D structures with up to 8 atoms per unit
cell. We have identified four main groups of structures: flat nanowires
(monatomic-height stripes) with triangular or triangular and "square" motifs,
stripes with larger holes, nanowires with an open tubular shape, and regular
nanowires. The diameter-dependent structural changes are discussed.
