Synthesis and Electronic Transport of Natural Superlattice Compounds

Abstract

The study of periodic structures and their impact on states of matter is essential in condensed matter physics. The analysis of this periodicity led to the modern understanding of electronic properties through the band structure. Advances in materials synthesis and discovery have led to precise control over electronic properties via control of the atomic structure. One family of materials in which this has been explored are van der Waals (vdW) materials. In addition to their study as bulk crystalline specimens, the two-dimensional nature of these materials enables the development of artificial heterostructures with a diverse range of electronic states of matter. The ability to in turn design bulk crystals containing such heterostructures would enable access to a broader range of experimental techniques and potential new electronic states. In this thesis, we present a synthesis study of natural superlattices composed of transition metal dichalcogenide (TMD) monolayers alternating with spacer layers. These superlattices belong to the TMD family with chemical formula MS₂, M = (V, Nb, Mo, W). We study one such compound, Sr-VS₂, through electronic transport measurements including evidence for an insulating state therein. We further discuss syntheses of Group-VI TMD superlattices and the potential physics such systems may support.