Theoretical investigations of novel zinc oxide polytypes and in-depth study of their electronic properties

Zinc oxide is one of the most investigated compounds in materials science, both experimentally and theoretically, while in nature it appears only rarely, as the mineral zincite. Yet there are still many open questions: Is it still possible to observe or synthesize new modifications of zinc oxide? And can we improve the properties of a material that has already been investigated in thousands of studies? What is the connection between zincite, zinc sulfide and zinc oxide, and can we finally explain the controversial mineral matraite? In short, Yes: the answer to these questions is polytypism. We identify a multitude of possible stable polytypes for zinc oxide, and we show that by varying the stacking order, we can fine-tune the electronic properties such as the direct primary and secondary band gaps in zinc oxide without adding dopant atoms.