Mid Term Review

Towards polariton condensation in atomically-thin semiconductors

Mr Matthias Wurdack
PhD student, Nonlinear Physics Center
ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET)

Exciton-polaritons (polaritons herein) are bosonic quasiparticles with unique physical properties arising from strong coupling between excitons and confined photons. Since their first demonstration, exciton-polaritons became a convenient platform for studies of collective quantum effects such as Bose-Einstein condensation and superfluidity. To date, the most striking effects were cleanly demonstrated in GaAs-based microcavities due to the very low defect densities in those MBE-grown structures. However, polaritons in GaAs quantum wells can only exist at cryogenic temperatures, which limits practical applications for future optoelectronics. To overcome this limitation, polariton research groups are pushing towards room temperature operation by utilizing more stable excitons in other materials, e.g., in monolayers of transition metal dichalcogenide crystals (TMDCs). 

Excitons in TMDC monolayers, with their unique valley degree of freedom, have attracted intense attention during the past decade due to possible applications in spintronics and quantum technologies. Polariton condensation and superfluidity in this material class can potentially allow dissipationless transport at room temperature and form the basis for future optoelectronic devices with ultra-low energy consumption. However, polariton condensation in this material class has not been realized yet, despite significant research efforts directed towards this goal. 

In my Mid-term Review, I will discuss the challenges that need to be overcome in order to observe polariton condensation in TMDC monolayers, our progress towards integrating TMDCs into optical microcavities, and our current results on passivating and integrating the TMDC monolayers into a dielectric environment without quenching their excitons.

Zoom event : https://anu.zoom.us/j/99625845353?pwd=YzBWZjZyRWVCcXRFdkRLNmFuNXJvQT09

Password : 726726

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