First-principles investigation of the electronic properties of interfaces

Abstract

Modern technology depends on the interfaces between materials. Nanomaterials and 2D systems are also promising for future energy and electronics applications. The much larger surface to volume ration of these systems compared to their bulk counterparts makes the interface properties even more important. Understanding the properties of interfaces is vital for technological advancement. First-principles calculations utilizing Density Functional Theory (DFT) can be applied to interfaces and nanostructures to improve the understanding of these systems. I have used these methods to investigate several systems with energy and electronics applications. Several aspects of solar water splitting have been examined, leading to a method of calculating redox levels as well as alignments for amorphous materials. A derailed understanding of the hole transfer reaction on surfaces has also been developed, as well as an understanding of band edge engineering in the promising photocatalyst CoO. In the field if electronics, edge engineering possibilities have been discovered in MoS2, also leading to a general electron counting method that is widely applicable. The nature of the insulating state as well as a model for the transition to the superconducting state has been proposed in (Li,Fe)OHFeSe. The interface between STO and FeSe has also been investigated and the issues are discussed.