Electron metasurfaces in graphene

For electron optics in graphene, the propagation effect has so far been the only physical mechanism available. The resulting optics-inspired electronic components are large in size and operate at low temperatures to avoid violating the ballistic transport limits. Here, electron metasurfaces, i.e., electronic counterparts of optical metasurfaces, are introduced for graphene electronics. We theoretically implement various angles of electron beam bending, as well as beam splitting at corresponding angles in the same metasurface with the functionalities switched freely by controlling the applied gate biases. The wavefront of electron beams is shaped within a distance far below the ballistic transport distance at room temperature, allowing for the realization of optics-inspired electronic devices that can operate under ambient conditions. The concept of metasurface electron optics, based on elaborate design of more complex spatial phase patterns, might also open up a promising avenue for achieving more appealing applications such as electron metalenses, metasurface holography, as well as metasurface-based digital coding technology in graphene.