In 1884, Edwin Abbott wrote the novel Flatland: A Romance in Many Dimensions as a satire of Victorian hierarchy. He imagined a world that existed only in two dimensions, where the beings are 2D geometric figures. The physics of such a world is somewhat akin to that of modern 2D materials, such as graphene and transition metal dichalcogenides, which include tungsten disulfide (WS₂), tungsten diselenide (WSe₂), molybdenum disulfide (MoS₂) and molybdenum diselenide (MoSe₂).

Modern 2D materials consist of single-atom layers, where electrons can move in two dimensions but their motion in the third dimension is restricted. Due to this ‘squeeze’, 2D materials have enhanced optical and electronic properties that show great promise as next-generation, ultrathin devices in the fields of energy, communications, imaging and quantum computing, among others.

Typically, for all these applications, the 2D materials are envisioned in flat-lying arrangements. Unfortunately, however, the strength of these materials is also their greatest weakness—they are extremely thin. This means that when they are illuminated, light can interact with them only over a tiny thickness, which limits their usefulness. To overcome this shortcoming, researchers are starting to look for new ways to fold the 2D materials into complex 3D shapes.