Amorphous boron arsenide

Abstract

The short-range order and electrical properties of amorphous boron arsenide (BAs) are evaluated by means of ab initio molecular dynamics simulations. The amorphous model is obtained from the fast solidification of the BAs melt and consists of B-rich and As-rich domains. The average coordination number of B- and As-atoms are found as 4.97 and 3.34, respectively. B-atoms have a tendency to form pentagonal pyramidal-like configurations as commonly seen in boron or boron rich materials. Yet B-12 molecules do not develop in the system but the formation of a B-10 cluster is perceived in the network. On the other hand, As-atoms have a trend to structure chain-like motifs and four-membered rings. Amorphization yield about 31% volume expansion in the amorphous network. All these findings reveal that the model shows strong chemical disorder and its short-range order is considerably different than that of the crystal. Amorphization-induced metallization is proposed for BAs.