| We use ab initio molecular dynamics simulations to examine liquid semiconductors. Our method uses quantum interatomic forces, computed using the pseudopotential density functional method. We use this method to examine a SiGe alloy (liquid and amorphous phases), liquid CdTe and liquid ZnTe. We calculate structural, electronic and dynamical properties of these liquids and amorphous solids.; We find that l - SiGe has a predominantly random structure with a slight phase separation of Si-Si and Ge-Ge bonds. Upon cooling, the structure of l - SiGe changes significantly from a more close packed-like structure to an open tetrahedral arrangement of atoms. Also, it is shown that the conductivity of l - SiGe has a metallic character, while a - SiGe has a semiconductor-type conductivity.; We find CdTe remains semiconducting upon melting. Liquid CdTe retains its tetrahedral environment with a coordination number of about four. Further heating leads to substantial structural changes with transformation to a more close-packed atomic structure. We also find that in liquid CdTe, near the melting temperature, atoms of Te form branched chains. As the temperature increases these chains disrupt, become shorter and transform to form close-packed clusters.; We find that l - ZnTe retains its open tetrahedral environment upon melting with a coordination near four. In addition, we find that atoms of Te in l - ZnTe often form transitory chains just as in l - CdTe. We compare our calculated structure factor to experiment and also determine the conductivity of the melt: l - ZnTe has a semiconductor-like conductivity similar to l - CdTe. |
