Electrically tuned Josephson effects in exciton-polariton condensates

An exciton-polariton condensate can be considered as the charge neutral analog of a superconducting BCS state, which displays a variety of interesting mesoscopic phenomena such as the A.C. and D.C. Josephson effects. Recent microcavity studies of novel materials such as metal lead halide perovskites and transition metal dichalcogenides showed evidence for a higher binding energy for exciton-polaritons, which allows a more robust condensate at relatively higher temperature, thus allowing the possibility to develop coherent devices without requiring the cooling techniques for extremely low temperatures.

Here we propose an electrically tuned exciton-polariton device in analogy to a superconducting circuit.

The device is formed in a coplanar geometry parallel to the reflectors of the cavity, with lithographically defined regions hosting the 2-D exciton-polaritons serving as the left and right leads of a Josephson Junction.

The dynamics of this interacting bosonic gas give rise to a pair of Josephson-like equations, leading to oscillations in the condensate density and/or the condensate pseudo spin, analogous to Josephson oscillations in a superconducting junction. By applying a spatially varying in-plane electric field, we introduce a chemical potential difference between the left and right leads and focus on the tunneling dynamics. We calculate the characteristic frequency of oscillation and related optical and electrical experimental signatures. Based on this model we discuss the quantum coherent behavior of driven systems and explore their behaviors at higher temperatures.