Optical anisotropy of bismides induced by spontaneous ordering of bismuth atoms

Bismides are in a focus of wide-range studies due to their potential use in IR optoelectronic and solar elements.
Our recent optical investigations of GaAsBi bismides revealed a polarization anisotropy of their fundamental-bandgap optical transitions. The structural characterization of the samples, based on atomic-resolution microscopy and XRD, shows that they also exhibit a spontaneous ordering of Bi atoms along the direction, which corresponds to an optical axis of observed anisotropy. This allows for a hypothetic assumption that the optical anisotropy of bismides is induced by atomic ordering.
Both the ordering and the optical anisotropy of bismides were not widely investigated and the topic is novel. There are only few papers on GaAsBi spontaneous ordering. No optical anisotropy studies of bismides have been reported in literature to this date.
The goal of the present work is to elucidate the physical origin of the optical anisotropy of bismides.
The optical anisotropy implies a specific electronic structure and, therefore, a variation of other physical properties, which is crucial for further development of bismides and scope of their applications.
For more information, please contact the theme supervisor V. Karpus.