Single-slit electron diffraction analog in a graphene based device

Graphene’s unique properties steming from its ability to host massless Dirac fermions, continue to make it a vital material for various applications. This raises questions about measuring wavelike behavior, particularly in the context of Dirac fermions. These devices, when coupled with improved fabrication techniques, offer a foundation for diffraction based switch mechanisms. This talk presents an observation of single slit diffraction by massless Dirac fermions in graphene, fully encapsulated with hexagonal boron nitride on a back-gated SiO₂ substrate. These massless Dirac fermions exhibit an effective de Broglie wavelength corresponding to their Fermi energy and applied gate voltage. Nanometer-scale device designs were implemented to fabricate a single-slit followed by five detector paths. Predictive calculations were employed to interpret the observations by modelling the ideal wave propagation scenarios within the designed devices to provide an accurate description of the observed phenomenon. The experiments were conducted both at room temperature and at 190 K. The colder temperature revealed an exaggerated asymmetry in the electrical properties of electrons and holes, with differing Fermi velocities near the K point considered as a potential contributing factor. This observation of single-slit diffraction and the associated device concept hold promise for the development of diffraction switches with versatile applications in various fields.