The influence of Zn vacancy on thermal conductivity of E β-Zn4Sb3: A molecular dynamics study

In our present work, the effect of the Zn-vacancy concentration on the lattice thermal conductivity of beta-Zn4Sb3 at room temperature is studied by using the nonequilibrium molecular dynamics approach. Along both the x-and z-axes, the heat flux and the temperature gradient exponentially decay and increase respectively. The lattice thermal conductivity of the single crystal bulk beta-Zn4Sb3 rapidly decreases when there exists Zn atom vacancy, and then the lattice thermal conductivity slowly falls further with the growing Zn atom vacancy proportion, which suggests that the Zn atom vacancy (n(v)) to the lattice thermal conductivity (k(vac)) leads to a scaling law of k(v) similar to n(v)(-alpha). This phenomenon is attributed to the fact that the existence of vacancy scattering can significantly decrease the mean free path. When the vacancy proportion of Zn atom reaches 10%, that is the vacancy model of beta-Zn4Sb3, the lattice thermal conductivity of beta-Zn4Sb3 is 1.32 W/mk and 1.62 W/mk along the x-and z-axes respectively, which drops by similar to 90% than that of its full occupancy model.