Valleytronics: Opportunities, Challenges, and Paths Forward

A lack of inversion symmetry coupled with the presence of time‐reversal symmetry endows 2D transition metal dichalcogenides with individually addressable valleys in momentum space at the K and K′ points in the first Brillouin zone. This valley addressability opens up the possibility of using the momentum state of electrons, holes, or excitons as a completely new paradigm in information processing. The opportunities and challenges associated with manipulation of the valley degree of freedom for practical quantum and classical information processing applications were analyzed during the 2017 Workshop on Valleytronic Materials, Architectures, and Devices; this Review presents the major findings of the workshop. Valleytronics offers a new paradigm in information processing based on the optical and electrical manipulation of the valley degree of freedom in 2D materials with broken inversion symmetry. Delivering impactful, real‐world technology based on valleytronics requires a concrete assessment of the advantages over existing technologies and an analysis of the key challenges that must be overcome.