Thermal Stability of Single Walled SiGe Nanotube with Vacancy Defects: a Molecular Dynamics Simulation Study

The aim of this investigation was to study thermal properties of perfect and imperfect single-walled Si-x%Ge (atomic percentages) armchair nanotubes. We have performed molecular dynamics simulation computations based on Tersoff many body potential in the constant temperature and pressure ensemble. The temperature and pressure of the nanotube were controlled by a Nose-Hoover thermostat and barostat, respectively. The phase diagram of the Si-x%Ge nanotube was built by changing atomic percentages of Ge and then melting the nanotube. Our results show that cohesive energy increases, isobaric heat capacity, and thermal stability of Si-x%Ge nanotube decrease with increasing Ge composition in the nanotube. Moreover, we created 0.5, 1, 1.5, …, 4 at% vacancy defects in the nanotubes to study thermal properties of imperfect Si-Ge nanotubes. Finally, the average of formation energy per defect was calculated as 0.39 eV by MD simulation.