Project Details
Projekt
Fingerprinting, tailoring, and transporting excitons in strained 2D heterostructures
Applicant
Professor Dr. Kirill Bolotin
Subject Area
Experimental Condensed Matter Physics
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 535356462
Heterostructures of 2D semiconductors feature emergent phenomena ranging from excitonic condensation to interactions-driven ferromagnetism arising in moiré lattices. New tools to interrogate and control these phenomena are needed. The overarching goal of this project is to develop an experimental toolbox based on strain engineering to fingerprint, generate, and transport excitons in semiconductor 2D heterostructures. By “fingerprinting”, we mean identifying the position of excitons in momentum space, thereby unraveling the character of currently debated states. To accomplish this, we use the fact that different parts of the Brillion zone of 2D heterostructures shift with strain at different rates. By “tailoring”, we mean creating emergent states only existing in strained samples. One such state is created when different types of excitons (e.g. free and localized) are brought into an energetic resonance under strain, thereby producing a new hybridized state. A different kind of state is generated when the strain changes the lattice constant or breaks the symmetry of the moiré pattern. Finally, by “transporting”, we mean using tunable inhomogeneous strain fields to produce an effective force acting on excitons. That will result in long-range funneling for different excitonic species, the creation of localized states due to confinement, and the generation of correlated states at high excitonic densities. All these experiments rely on unique techniques we recently developed to apply homogenous or inhomogeneous strain with in-situ tunable magnitude up to 3% to clean 2D materials and their heterostructures at cryogenic temperatures. We will collaborate with other consortium projects towards imaging strained moiré heterostructures, time-resolved excitonic transport measurements, and theoretical modeling of strained moirés.
DFG Programme
Priority Programmes
