Determining crystal phase purity in c-BP through X-ray absorption spectroscopy.

We employ X-ray absorption near-edge spectroscopy at the boron K-edge and the phosphorus L-edge to study the structural properties of cubic boron phosphide (c-BP) samples. The X-ray absorption spectra are modeled from first-principles within the density functional theory framework using the excited electron core-hole (XCH) approach. A simple structural model of a perfect c-BP crystal accurately reproduces the P L-edge, however it fails to describe the broad and gradual onset of the B K-edge.