Heterointerfaces of two-dimensional materials are an ideal design space for tuning electronic materials’ properties due to the simplicity of stacking different layers to combine their versatile electronic properties. One of the most fascinating examples of this is the proximity effect between magnetic and valleytronic materials. Materials with inherent time-reversal symmetry, such as transition metal dichalcogenides, can have two equivalent electron valley states in momentum space. Applying a magnetic field breaks the symmetry between these states, creating a degree of freedom with many applications in information processing and quantum communication.  Valley symmetry can also be broken by an adjacent two-dimensional magnetic layer, with the proximity-induced valley splitting potentially much stronger than can be achieved with practical external field strengths. The interlayer exchange interaction depends strongly on the orbital hybridization between the two materials, which in turn is influenced by the relative energy alignment of their band edges. Experimentally, this has been adjusted by placing the materials under a strain gradient, which not only tunes the exchange interaction but also creates local extrema in the bands, and traps excitons into a highly localized state that emits individual photons.

This talk will discuss our latest results on a selected set of chalcogenide heterointerfaces. In particular, we will present our density functional theory computational screening results on a wide range of heterointerfaces with a potential for valley splitting. In addition to presenting our findings in terms of the most promising systems, the associated challenges in the computations will be highlighted. We will also illustrate the formation of Moire patterns in large twisted interfaces, and examine these patterns’ influence on the magnetic interaction and electronic structure. We will close by addressing the interplay of defects and band alignment in these complex two-dimensional material systems that can potentially lead to single photon emission.