Tunable Moiré Potentials in 2D-Heterostructures using Anisotropic Strain

• Applicants: Professor Dr. Fei Ding; Professor Dr. Jonathan J. Finley; Professor Dr. Rolf J. Haug
• Subject Area: Experimental Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 443274490

This project focuses on the exploration of strongly correlated electronic and excitonic phases in strain tunable van der Waals heterostructures formed from graphene and transition metal dichalcogenides. By synergistically combining highly local optical methods, having high spatial (<1µm) and temporal (~1ps) resolution, with non-local quantum (magneto-)transport approaches, we will probe strongly correlated quantum states in strain-tunable moiré superlattices. Strain modifies the symmetry of the moiré potential and is therefore a tuning mechanism for interactions. We will further modify the particle (electron, exciton, trion) density, lattice temperature and the presence of energy input (driving). Experiments will elucidate emergent phenomena (correlation effects and condensation), test the strength of inter-particle interactions, measure the spectrum of low-lying excitations and assess the impact of driving away from equilibrium. By combining optical and transport methods, we open the way to control of spin and valley degrees of freedom, perform time resolved studies of correlated phases and, thereby, understand emergent collective states. Three leading groups are involved, two at the Leibnitz Universität Hannover and one at the Technical University of Munich, each synergistically bringing the necessary expertise in the fabrication of vdW heterostructures, arbitrary strain control via multi-axis piezoelectric actuators, spatially resolved CW and time-resolved optical experiments and quantum (magneto-)transport spectroscopy. The mid-term goal is to realize beyond state-of-the-art moiré systems and explore quantum many body physics in 2D heterostructures. By exploiting interactions, the long-term vision is to realize artificial quantum solids and a tunable quantum simulator platform.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2244: 2D Materials – Physics of van der Waals [hetero]structures (2DMP)
• Co-Investigator: Andreas Stier, Ph.D.