Strong Screening Effect on Radial Polarization of Metallic NbS ₂ Nanoscrolls

The energetics and electronic structure of NbS2 nanoscrolls were examined by using density functional theory. The NbS2 nanoscrolls with an unrolled length of 22.7 nm are energetically more stable than the corresponding NbS2 nanoribbons because of substantial van der Waals interactions between adjacent shells that are enough to compensate for the energy cost of curvature. Among all of the nanoscrolls studied here, the nanoscroll with an innermost radius of 1.5 nm is the most stable. NbS2 nanoscrolls are metals with a large density of states at the Fermi level, resulting in a strong field screening ability. The electronic structure of NbS2 nanoscrolls is remarkably insensitive to scroll geometry and atomic position because of the screening ability of the internal electric field induced by the curvature.