Ab initio molecular dynamics simulation of liquid CdTe and GaAs: Semiconducting versus metallic behavior

All semiconductors of group IV, such as silicon, and III-V materials, such as gallium arsenide, assume metallic behavior when melted. This is in contrast to some II-VI semiconductors such as CdTe which retain their semiconducting behavior in both the liquid and the solid state. In order to understand this difference, we have performed ab initio molecular dynamics simulations of liquid GaAs and CdTe. Using the Kubo-Greenwood formalism, we predict the conductivity of both liquids and confirm the differences observed experimentally. We relate the conductivity differences between II-VI and III-V semiconductors to strong structural differences occurring within the melt. [S0031-9007(98)07783-7].