Thermal conductivity for single-walled carbon nanotubes from Einstein relation in molecular dynamics

• MD simulation method with Einstein relation and modified formula of energy moment are used to calculate the thermal conductivity.
• Apply this method on individual single-walled carbon nanotubes(SWNTs).
• The thermal conductivity of SWNTS is investigated as a function of three tubes parameters at room temperature and also near room temperature.
• The tube parameters are radius, length and chirality of the SWNTs.

Equilibrium molecular dynamics based Einstein relation with an appropriate definition for integrated heat current (i.e., with modified energy moment) are combined to quantify the thermal conductivity of individual single-walled carbon nanotubes, armchair, zigzag and chiral tubes. The thermal conductivity has been investigated as a function of three parameters, tube radius, length and chirality at and near room temperature with Brenner potential model. Thermal conductivity is found to have unusually high value and varies with radius, length and chirality of tubes. Also the thermal conductivity at temperature range from 50 to 100 K is found to have a maximum value. For 12.1 nm tube length, the thermal conductivity has converging trend which its value dependents on the tube radius and chirality. Tubes with large radius have lower values of thermal conductivity. Furthermore, the results show that armchair tubes have large values of the thermal conductivity comparing with zigzag and chiral tubes. It seems possible to uncover carbon nanotubes thermal properties based on measurements having heat dependence by adding another methods for calculations.