Thermal Conductivity Of Te-Based Materials Investigated By Molecular Dynamics

Heat transfer property is one of essential physical and chemical properties of materials, especially in electronics, optoelectronics and thermoelectrics mate-rials. For semiconductors, heat transfer is mainly depends on the transport of phonons. Therefore, it is necessary to investigate phonon transport further in or-der to obtain the heat transfer property of a material. In this work, the thermal conductivity of Zn-Cd-Hg-Te system has been calculated by equilibrium molec-ular dynamics (EMD) method. A Stillinger-Weber (SW) potential is used in the simulations to descript the atomic interactions. The main simulated results are as follows,Firstly, the thermal conductivities of zinc-blende structure CdTe with per-fect lattice and contained point defects have been simulated by EMD method based on Green-Kubo formalism, respectively. The results show that the thermal conductivities of CdTe bulk decrease with the increasing temperature. The cal-culated thermal conductivities of perfect CdTe are an order of magnitude higher than that of experimental values. When the point defects have been taken into the simulation model, the calculated thermal conductivities are decrease to the same magnitude with the experimental values. The phonon density of states have been calculated and the results indicate that the thermal conductivities de-crease due to the phonons scattered by point defects.Secondly, the thermal conductivities of zinc-blende structure HgTe and CdxHg1-xTe solid solution have been calculated by EMD method based on Green-Kubo formalism. The calculated results also show that the thermal con-ductivities of HgTe bulk decrease with the increasing of temperature. The calcu-lated thermal conductivities of perfect HgTe are an order of magnitude higher than that of experimental values. When the point defects have been taken into account, the calculated thermal conductivities decrease to the same magnitude of the experimental values. For the CdxHg1-xTe (x=0.25,0.50,0.75), the ordered and random solid solution have been calculated, respectively. The results show that the thermal conductivity of ordered solid solutions is larger than that of random solid solutions.Finally, the thermal conductivities of zinc-blende structure ZnTe and CdxZn1-xTe solid solution have been calculated by EMD method based on Green-Kubo formalism, respectively. The results show that the thermal conduc-tivities of ZnTe bulk decrease with the increasing temperature. The calculated thermal conductivities of perfect ZnTe are in agreement with the experimental values. With the increasing vacancies concentrations, the thermal conductivity of ZnTe decreases. The impact of vacancies to thermal conductivity decreases with the increase of temperature. For the CdxZn1-xTe (x=0.25,0.50,0.75), or-dered and random solid solution have been calculated, respectively, in this work. The results also show that the thermal conductivity of ordered solid solutions is larger than that of random solid solutions.