Engineered Nanomaterials
Project Modules
Synthetic superlattices and quantum simulation
Superlattices are artificial, periodic potentials which are used to confined particles and quasiparticles such as atoms, electrons, or excitons. If the trapped quasiparticles are allowed to interact, the resulting many-body state can capture essential behaviors of canonical quantum many-body theories (e.g. the Hubbard model). Such artificial quasiparticle lattices are often called analogue quantum simulators. A bit like a quantum wind tunnel, the quantum simulator serves as an engineerable scale model of a real physical system (electrons or other particles in a real crystalline solid) which allows us to probe complicated many-body physics with a high level of control. Such many-body physics are often hard to describe or predict theoretically, so our quantum simulators provide a route to benchmark leading theories and discover new phases of matter beyond current theoretical predictions.
Our approach to quantum simulation is to create superlattices in 2D semiconductors by engineering an artificial electrostatic potential. This is accomplished by applying a bias voltage between a monolayer semiconductor and a nearby thin graphite layer which has been patterned with a periodic array of holes, generating a periodic potential/electric field profile in the 2D semiconductor layer which can trap charges. The depth of the superlattice potential can be easily tuned, and any lattice geometry can be implemented due to our top-down fabrication approach. We probe the superlattice devices using a combination of optical spectroscopy, relying on the natural sensitivity of the optically-active excitons to the correlated behavior of the charges in the superlattice, complemented by charge transport measurements.
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