STRUCTURE AND PROPERTIES OF AMORPHOUS GALLIUM-ARSENIDE BY TIGHT-BINDING MOLECULAR-DYNAMICS

We present and discuss the room-temperature structural, vibrational, and electronic properties of a-GaAs, as obtained by a tight-binding molecular-dynamics quenching of the liquid from 1600 K. An interesting comparison is also made with the overcooled liquid at 800 K, where solidlike and liquidlike features do coexist. At variance with previous ab initio calculations, we have been able to produce a good amorphous sample without introducing ad hoc moves of atoms, favoring a preselected distribution of point defects. Our results are in rather good agreement with the overall structural properties of a-GaAs, as deduced from experiments, and provide a detailed microscopic characterization of such a material.