Narrow Results

First-principle calculations and density functional theory (DFT) have been combined to comparatively investigate the band structure, phonon spectrum, and optical and elastic properties of one-dimensional nanotube-like Bi. Our calculation reveals that Bi exhibits metallic properties, based on the valence band top (VBT) that lies above the conduction band bottom (CBB), and this is known as a negative bandgap. The optical bandgap is found to be very small, with a value of 257meV. The absorption coefficient is observed to be very high, up to $1.89\times 10^5$cm${}^{-1}$. This quantity falls within the vacuum ultraviolet (VUV) region. According to our reflectivity data, up to 82% of light has been reflected, which could be suitable for optical coating. Our elastic calculations further suggest the Bi-material should be brittle and covalent. Our data provide a deep understanding of various properties of Bismuth and could be useful to other theoretical and experimentalists.