Investigation into thermoelectric properties of M (M=Hf, Zr) X2(X=S, Se, Te) nanotubes using first-principles calculation

This study investigates the electronic and thermoelectric properties of (5, 0) single-wall M (M = Hf, Zr) X2(X = S, Se, Te) nanotubes by using first-principles calculations and semi-classical Boltzmann theory. Effective mass (m*), Deformation potential (DP), Stretching modulus (C) Relaxation time (tau) and mobility of charge carriers (mu), for each nanotube were calculated using the deformation potential theory. The tubes, possess indirect bandgap varying between 1.12 and 0.075 eV and it is found that band gap was reduced upon increasing the chalcogen atomic size. Electrical conductivity (sigma ), Seebeck coefficient (S), electronic thermal conductivity (kappa e) and electronic part of Figure of merit (ZT) as a function of doping level were obtained for each nanotube. Our systematic study can recommend that a good thermoelectric material with a high Seebeck coefficient and merits be chosen.