STRUCTURE AND ELECTRONIC-PROPERTIES OF AMORPHOUS INDIUM-PHOSPHIDE FROM FIRST PRINCIPLES

We report detailed and extensive First-principles molecular-dynamics ( MD) simulations of the structure and electronic properties of amorphou s InP produced by rapid quenching from the liquid. The structure of th e material is found to be strongly ordered chemically, even though the re is a significant number of coordination defects and despite the pre sence of odd membered rings. We find, as a consequence, that there exi st ''wrong bonds'' in the system, in an amount of about 8%; these resu lt from the presence of coordination defects, not of local composition fluctuations, as has been conjectured. The system, in fact, is found to be overcoordinated, which might be the reason for the observe highe r density of a-InP compared to c-InP. We have also investigated the po ssibility of pressure-amorphizing InP. Our calculations indicate that the cost of a transformation of the compressed zinc-blende crystal int o an amorphous phase is so large that II is very unlikely that ii woul d take place.