DOE OSTI2020
Ga3AlN4 is Chalcopyrite-like structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are three inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four N3- atoms to form GaN4 tetrahedra that share corners with two equivalent AlN4 tetrahedra and corners with ten GaN4 tetrahedra. There are a spread of Ga–N bond distances ranging from 1.95–1.97 Å. In the second Ga3+ site, Ga3+ is bonded to four N3- atoms to form GaN4 tetrahedra that share corners with four equivalent AlN4 tetrahedra and corners with eight GaN4 tetrahedra. There are a spread of Ga–N bond distances ranging from 1.95–1.99 Å. In the third Ga3+ site, Ga3+ is bonded to four N3- atoms to form GaN4 tetrahedra that share corners with four equivalent AlN4 tetrahedra and corners with eight GaN4 tetrahedra. There is three shorter (1.97 Å) and one longer (1.98 Å) Ga–N bond length. Al3+ is bonded to four N3- atoms to form AlN4 tetrahedra that share corners with two equivalent AlN4 tetrahedra and corners with ten GaN4 tetrahedra. There is two shorter (1.91 Å) and two longer (1.92 Å) Al–N bond length. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded to three Ga3+ and one Al3+ atom to form corner-sharing NAlGa3 tetrahedra. In the second N3- site, N3- is bonded to two Ga3+ and two equivalent Al3+ atoms to form corner-sharing NAl2Ga2 tetrahedra. In the third N3- site, N3- is bonded to four Ga3+ atoms to form corner-sharing NGa4 tetrahedra. In the fourth N3- site, N3- is bonded to three Ga3+ and one Al3+ atom to form corner-sharing NAlGa3 tetrahedra.