Revealing the 1D Nature of Electronic States in Phosphorene Chains

Phosphorene, a 2D allotrope of phosphorus, is technologically very appealing because of its semiconducting properties and narrow bandgap. Further reduction of the phosphorene dimensionality may spawn exotic properties of its electronic structure, including lateral quantum confinement and topological edge states. It is demonstrated that dispersions measured along and perpendicular to the phosphorene chains self‐assembled on Ag(111) reveal pronounced electronic confinement resulting in a 1D band, flat and dispersionless perpendicular to the chain direction in momentum space. Density functional theory calculations reproduce the 1D band for the experimentally determined structure. It is shown that phosphorene chains aligned equiprobably to three directions of the Ag(111) surface can be characterized by angle‐resolved photoemission spectroscopy because the three rotational variants are separated in the angular domain. A semiconductor‐to‐metal phase transition is predicted upon increasing the density of the chain array, a promising approach to band structure engineering.