Current-induced spin polarization in gallium nitride

Electrically generated spin polarization is probed directly in bulk GaN using Kerr rotation spectroscopy. A series of n -type GaN epilayers are grown in the wurtzite phase both by molecular beam epitaxy and metalorganic chemical vapor deposition with a variety of doping densities chosen to broadly modulate the transverse spin lifetime, T₂^*. The spin polarization is characterized as a function of electrical excitation energy over a range of temperatures. Despite weak spin-orbit interactions in GaN, a current-induced spin polarization is observed in the material at temperatures of up to 200 K.