Mechanical property and thermal conductivity of pentadiamond: A comprehensive molecular dynamics study

Although most of conventional carbon materials show super electricity-conducting performance, the excellent heat-conducting property always hinders their applications in thermoelectric area. The present work shows that such issue may be alleviated by employing the newly proposed carbon allotrope named pentadiamond. Comprehensive studies on mechanical property and thermal conductivity of pentadiamond via molecular dynamics (MD) simulations in this work reveal that pentadiamond possesses exceptional properties such as very light weight, extremely high specific Young's modulus and remarkably low thermal conductivity compared with other carbon allotrope structures (e.g. diamond, graphene and carbon nanotube, etc.). The mechanical property of pentadiamond is of great dependence on the crystal orientation under different loading conditions. The increasing temperature has a weakening effect on the mechanical property. Besides, the thermal conductivity of pentadiamond structure is dependent on the crystal orientation and the value along the crystal orientation [1 1 0] is slightly larger. The thermal conductivity decreases with increase in temperature. With the increase in the size of the pentadiamond, the thermal conductivity increases to a limit value which is determined as about 28 W/mK along the crystal orientation [1 1 0] via extrapolation method. Such findings can be of great help in the application of pentadiamond in thermoelectric field.