Structural and electronic evidence of boron atomic chains

The structure and chemical state of a boron chain, isoelectronic to polycumulene, were obtained with a combination of positron diffraction, photoelectron spectroscopy, and first-principles calculations. In the present work, an array of boron chains was found in a copper boride layer on a metal crystal substrate. The band structure of this material was determined to be electronically doped and hybridized by neighboring copper atoms. These boron atom chains exhibit a unique electrophilic character that is specific to the element. The properties of boron chains in the copper boride layer and the substrate effect are systematically investigated together.