Arsenic Monolayers Formed by Zero-Dimensional Tetrahedral Clusters and One-Dimensional Armchair Nanochains

One-dimensional (1D) arsenene nanostructures are predicted to host a variety of interesting physical properties including antiferromagnetic, semiconductor-semimetal transition and quantum spin Hall effect, which thus holds great promise for next-generation electronic and spintronic devices. Herein, we devised a surface template strategy in a combination with surface-catalyzed decomposition of molecular As₄ cluster toward the synthesis of the superlattice of ultranarrow armchair arsenic nanochains in a large domain on Au(111). In the low annealing temperature window, zero-dimensional As₄ nanoclusters are assembled into continuous films through intermolecular van der Waals and molecule-substrate interactions. At the elevated temperature, the subsequent surface-assisted decomposition of molecular As₄ nanoclusters leads to the formation of a periodic array of 1D armchair arsenic nanochains that form a (2 × 3) superstructure on the Au(111) surface. These ultranarrow armchair arsenic nanochains are predicted to have a small bandgap of ∼0.50 eV, in contrast to metallic zigzag chains. In addition, the Au-supported arsenic nanochains can be flipped to form a bilayer structure through tip indentation and manipulation, suggesting the possible transfer of these nanochains from the substrate. The successful realization of arsenic nanostructures is expected to advance low-dimensional physics and infrared optoelectronic nanodevices.