IRG 1, Materials Science of Quantum Phenomena in van der Waals Heterostructures, combines two-dimensional van der Waals materials into pristine layered heterostructures. Under an existing MIRT program, this team has demonstrated successful collaboration to develop proof-of-concept heterostructures with unprecedented size, perfection, and complexity, giving us the ideal building blocks for the current effort. This IRG focuses on three research thrusts: (1) Expanding the class of available materials, particularly using synthetic methods that produce large-area films; (2) Measuring and controlling the properties of atomically thin vdW materials in a protected, ultralow-disorder environment; and (3) Creating new interfaces that exhibit emergent electronic phenomena.