Structural, Electronic, and Thermoelectric Properties of BiSb Nanotubes

The structural, electronic, and thermoelectric properties of BiSb nanotubes are investigated using a multiscale approach which combines the first-principles pseudopotential method, semiclassic Boltzmann theory, and molecular dynamics (MD) simulations. Our calculations indicate that the gear-like nanotubes (g-NTs) are energetically more favorable than their hexagonal counterparts (h-NTs). All the g-NTs are found to be semiconducting and their electronic transport coefficients are calculated within the relaxation time approximation. At room temperature, the Seebeck coefficients exhibit obvious peaks near the band edge and their absolute values are very large and increase monotonically with increasing band gaps of the nanotubes. The MD simulations show that the investigated BiSb nanotubes have very low lattice thermal conductivity. The significantly enhanced ZT value suggests that by appropriate doping the BiSb nanotubes could be excellent candidates for the thermoelectric applications.