Optical Properties and Electronic Structure of Spinel ZnRh2O4

The electronic structure of normal spinel structure ZnRh2O4 is investigated using combined optical properties measurements and density functional calculations. We find semiconducting behavior with an indirect band gap between crystal field split Rh 4d levels, with a t2g valence band and an eg conduction band. The band gap is found to be ∼1.2 eV based on a comparison of the calculated and measured optical conductivities. The results are discussed in terms of potential photoelectrochemical applications.