Structural and Electronic Properties of SmGaGe2O7 Studied by First Principles Methods

The crystal structure and electronic properties of the samarium gallium digermanate SmGaGe2O7 have been studied for the first time using first principles quantum-mechanical methods. The lattice parameters and the position of ions obtained in the generalized gradient approximation agree with experimental data. The material is shown to be an indirect band gap semiconductor with a band gap of 2.45 eV. Its valence band is formed by oxygen p-states, with an insignificant contribution of other states of the other atoms. Its conduction band is formed by gallium and germanium s- and p-states, with a small contribution of oxygen p-states and samarium d-states, located ≈1 eV from the conduction band bottom. The material contains charge carriers differing in effective mass.