Electronic and optical properties of single-walled GaN nanotubes from first principles

There is current experimental interest in fabricating GaN nanotubes for possible optoelectronics/luminescence applications. To date, {\it ab initio} studies of these potentially interesting systems have used ground-state density functional theory which has well-known shortcomings when used to predict electronic excitations. We report on our {\it ab initio} predictions of the electronic and optical properties of single- walled GaN nanotubes using electronic Green's functions within the GW-Bethe Salpeter Equation formalism. We present results the nanotube band structures, optical spectra, excitonic states, and likely luminescence properties.