Fingerprinting, tailoring, and transporting excitons in strained 2D heterostructures

Principal investigator

Kirill Bolotin, Freie Universitat Berlin [webpage]

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Abstract

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. By “tailoring”, we mean creating emergent states only existing in strained samples. One such 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.

These experiments rely on techniques we recently developed to apply homogenous or inhomogeneous strain with in-situ tunable magnitude >2% 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 modeling of moirés.