Dirac antidot superlattices for electrons in III-V semiconductors – Dirac-III-V

The project aims at studying electrons confined in quasi two-dimensional (2D) artificial honeycomb lattices specifically designed to generate complex band structures, including Dirac cones and non-trivial flat bands. The superlattices, which can be seen as artificial graphene materials, will be obtained by turning conventional III-V 2D electron gases formed inside semiconductor heterostructures into triangular antidot lattices at the limit of quantum confinement. Guided by predictive atomistic tight-binding calculations, periodic potential modulations will be induced in epitaxially-grown InGaAs/InP or InGaAs/AlInAs heterostructures by either lateral metallic gates or by inclusions of barrier materials. The patterns will be defined by high-resolution e-beam or block copolymer lithographies pushed to their limit in order to reach lattice parameters (periodicity) between 45 and 10 nm, allowing to obtain Dirac cones covering energy ranges up to tens of meV. Motivated by the interest in finding new types of quantum states which can be manipulated in tunable solid-state devices, state-of-the-art low-temperature electron transport measurements and local-probe spectroscopy will be employed to reveal Dirac fermions and non-trivial band structures predicted in these artificial 2D materials. Magneto-transport experiments will be used to investigate the complex evolution of the energy bands when magnetic and lattice scales are comparable.