Optical gain for wurtzite GaN with anisotropic strain in c plane

We calculated band structures of (1100)-oriented GaN with various strains. We found that introducing anisotropic strain in the c plane separates heavy hole and light hole bands. We also found that a tensile strain in the (1100) plane makes the light hole band topmost. These two effects result in a reduction in the density of states at the valence band edge. In this way, we can significantly reduce the transparent carrier density to generate gain.