Opportunities in Two-dimensional Material Research

Two-dimensional (2D) atomic crystals, best exemplified by graphene, have emerged as a new class of material that may impact future science and technology. From a material physicist's point of view, 2D materials provides vast opportunities on two fronts. First, the reduced dimensionality in these 2D crystals often leads to novel material properties that are different from those in the bulk. Second, the entire 2D crystal is a surface, so it is possible to have better control of their material properties with external perturbations. In this talk I will illustrate these two points with examples. In particular, few-layer MnBi2Te4 is an intrinsic magnetic topological insulator, and its superior material quality has recently enabled us to observe the quantum anomalous Hall effect; we are also able to exfoliate high temperature superconductor Bi2Sr2CaCu2O8+d down to monolayer. We explore their electronic properties while the doping and dimensionality of the 2D systems are modulated.