Phase transition and instability in dimensionality-controlled artificial oxide crystals

The metal-insulator transition (MIT) is one of the fascinating physical phenomena in complex oxide system, and that has inspired the physics community during the last 20^th century. In particular, recent advances in atomically controlled growth of oxide material have enabled the realization of artificial crystals with customized dimensions. Herein, by combining density functional theory calculations with optical and electrical measurements, we investigate dimensionality-induced MIT in atomically well-defined SrRuO₃/SrTiO₃ (SRO/STO) superlattices. We note that SRO/STO superlattices favor an antiferromagnetic insulating state as the SRO layers are getting thinner, which indicates that MIT is strongly coupled with magnetic ordering. Furthermore, we find that electronic and magnetic instabilities in the two SRO unit cell induce thermally-driven MIT along with magnetic transition. Novel theoretical finding will be presented along with transport and optical observations.