Band structure calculation and crystal field induced electronic properties illustration for spinel CuGa2O4*

Abstract

In this paper, first-principle with generalized gradient approximation is used to study CuGa2O4. By comparing the simulation results with and without Hubbard U, we consider a band-gap of 4.59 eV and a lattice constant of 8.33 Å to be reasonable. In particular, it is found Cu 3d orbit split into different levels under tetrahedral field, and the spin empty orbit is 1.4 eV higher than the Fermi level. The deep reason is the Coulomb action of Cu and O on tetrahedron in different directions, through population and total energy analysis. These results indicate that CuGa2O4 is an intrinsic p-type material suitable for forming heterojunction with β-Ga2O3.