Electronic structures of ultra-thin tellurium nanoribbons.

The structural stability and electronic properties of monolayer and bilayer tellurium nanoribbons (TNRs) with different edge structures have been systematically investigated by means of first-principles calculations, revealing that the stability of both monolayer and bilayer TNRs largely rely on their width. Regardless of width, tip TNRs are metallic, while notch TNRs are p-type-like conductors. Interestingly, both mono- and bi-layer chain TNRs exhibit a semiconductor-to-metal transition as the width increases. The electronic structures of tip and notch TNRs are mainly determined by atomic reconstruction and the unsaturated electronic states on the edges. For chain TNRs, the origin of the semiconductor-to-metal transition can be attributed to the spontaneous in-plane electronic polarization across the ribbon. Our work reveals diverse electronic properties of one-dimensional elemental tellurium nanostructures, which considerably extend the potential applications of tellurene-based materials in nanodevices.