Exploration of Ti-doped CuGaO$_{2}$ delafossite*

In their most simple form, delafossite materials are of the form ABO$_{2}$ where A is a $+$1 metal cation and B is a $+$3 metal cation. Since O is in the -2 ionization state in the crystal, this results in a charge balanced and stable crystal. Delafossite materials have been studied for their p-type and n-type conductivity, however. This means that studied material samples have extra holes or electrons due to defects resulting in a net charge and thus allow for conductivity within the sample. Since types of defects inherent in a sample are due to the structure of the sample, they can then be doped with other elements to increase the p- or n-type conductivity. For example, CuCrO$_{2}$ is found to be of p-type defect chemistry, and when doped with Mg ($+$2), has a conductivity of 220 S cm$^{-1}$. In this research we computationally explore electronic properties of a new material, p-type CuGaO$_{2}$ doped with Ti ($+$2), and the resulting defects. This delafossite is a wide band gap semiconductor and has shown promise as a p-type material and a photocatalyst with the ability to reduce CO$_{2}$ to CO. An understanding of the doping of Ti in CuGaO$_{2}$ could lead to a material with a smaller band gap, better photocatalytic abilities, and enhanced conduction.