ATOMIC-STRUCTURE AND BONDING IN LIQUID GAAS FROM ABINITIO MOLECULAR-DYNAMICS

The structural and electronic properties of liquid GaAs are investigated using ab initio molecular-dynamics methods. In agreement with experiments, we find that liquid GaAs is metallic, with an average coordination number between 5 and 6. Analysis of the electronic-charge distribution shows that weakly ionic bonds, similar to those of crystalline GaAs, are still present in the liquid. At variance with the crystal, these bonds are not permanent, but are continuously formed and disrupted by atomic diffusion. On the average, however, almost 50% of the atoms of the first coordination shell are bonded to the central atom. Bonds between like atoms are very frequent (27%); three-atom clusters of a single species have a relative probability of 6%, while larger clusters occur only occasionally. © 1990 The American Physical Society.