Geometry and electronic properties of chiral phosphorene nanotubes

Abstract

Phosphorene nanotubes (PNTs) exhibit highly tunable electronic properties, yet research has largely focused on high-symmetry armchair and zigzag configurations. This work presents the first systematic study of the geometric and electronic properties of chiral PNTs. Using the Chiraltube software, a comprehensive set of 214 PNTs was generated and analyzed via a 2D zone-folding mapping approach. Subsequently, a representative subset of 48 chiral PNTs was selected for ab initio calculations covering the full chiral space. While the mapping method overestimates band gaps by directly inheriting monolayer features, it serves as a qualitative tool for specific chiral geometries-particularly armchair configurations and larger-radius tubes-by effectively capturing their subband density and dispersion profiles. Finally, this work details the evolution of structural stability and electronic properties as a function of radius and chirality, identifying clear direct-to-indirect band gap transitions driven by curvature effects, alongside metallic behavior in specific zigzag configurations.