Growing crystals inside van der Waals materials

Shaping low-dimensional crystals into precise geometries with low disorder is an outstanding challenge. I will present our recent progress in growing thin crystals of predefined geometry between van der Waals (vdW) materials. This is achieved by injecting molten material into a silica mold lined by vdW materials. Following this approach, we can directly produce ultraflat single crystals of bismuth, tin, and indium in various geometries, such as hall bars and nanowires, which are fully encapsulated within a vdW material. The combination of geometric control, quantum confinement, low disorder, and protection from oxidation unlocks a new regime for single-crystal quantum devices. I will discuss how this approach is helping us unlock the transport physics of two-dimensional bismuth and to realize unique mesoscopic heterostructures of vdW and non-vdW materials.