Molecular dynamics study on thermo-mechanical properties of bismuth telluride bulk

Molecular dynamics method is explored to investigate the effects of temperature on the mechanical and thermal properties of single crystal bismuth telluride from 0 K to 600 K, with potentials developed by Huang et al. The structural properties, lattice constants, linear thermal expansion coefficients, independent elastic constants were all calculated. The lattice constants were estimated by the size of box from the NPT simulation. The thermal expansion coefficient was calculated by a differential operation of the temperature dependence of the lattice constants. The tension and shear simulations have been conducted to calculate the elastic constants. The six independent elastic constants were calculated as a function of temperature from the stress-strain relations obtained from the NVT ensemble. All the calculated results are in good agreement with previous experimental and theoretical results. These agreements confirm the reliability of the present potential functions. The simulation results enable us to predict the mechanical and thermal properties of Bi₂Te₃ as an effective thermoelectric material in the whole range of its working temperature, and the data will be helpful for the practical manufacture and manipulation of Bi₂Te₃ thermoelectric devices.