Ab initio study of antisite defective layered Ge2Sb2Te5

By means of ab initio calculations, we have investigated the antisite defects in layered Ge2Sb2Te5 (GST). Our results show that both TeSb and SbTe antisite defective GST alloys are energetically favorable and mechanically stable. Furthermore, the presence of antisite defects results in the decrease in band gaps and hence the increase in the electrical conductivity, while shows slight effect on chemical bonding characters. Based on the present results, increased electrical conductivity and decreased thermal conductivity are expected by introducing antisite defects in GST related layered materials.