Indian J. Phys. 81(10) 1079-1093(2007) HI Electronic structure of ZnS nanotube: a density-functional study Sougata Pal, Biplab Goswami and Pranab Sarkar* Department of Chemistry, Visva-Bharati University, Santiniketan-731 235, West Bengal, India E-mail pranab. 69@yahoo co in Abstract : We present results of our theoretical calculations on structural, electronic and optical properties of ZnS nanotube The calculations are performed by using density-functional tight-binding (DFTB) method. We have considered both single-walled and double-walled nanotubes and studied the variation of radial distribution, Mulliken population, density of states and band gap as functions of both tube radius and tube helicity. Keywords : ZnS nanotube, single and double walled, electronic structure PACS Nos. : 72.80 Rj, 73.20.At, 61.46.+W 1. Introduction One-dimensional (1D) nanostructures such as semiconductor nanowires or nanotubes are of fundamental importance because of their potential use in both nanoscale engineering and nanotechnology [1-3]. Properties of these 1D nanostructures may sensitively depend on their structures, morphologies and sizes. The discovery of carbon nanotubes in 1991 [4] has stimulated extensive experimental and theoretical research concerning structures based on hexagon networks. The physical properties of carbon nanotube depends on the diameter as well as the helicity of the nanotube. Thus the armchair (n t n) carbon nanotubes are metallic while zigzag (n,0) carbon nanotubes are semiconducting [5-8]. The band gap can also be controlled by varying the diameter of the tube, thus allowing band gap engineering. The last couple of decades have witnessed an exponential growth of activities in this field, driven both by excitement of understanding new science and by the potential hope for technological applications. Recently, nanotubes made by non-carbon based inorganic semiconductor nanostructures popularly known as inorganic nanotubes have become the subject of extensive studies [9]. Their potential applications range from highly high porous catalytic and ultralight ^Corresponding Author © 2007 IACS