Exciton condensate at a total filling factor of one in Corbino two-dimensional electron bilayers

Magnetotransport and drag measurements on a quasi-Corbino two-dimensional electron bilayer at a total filling factor of 1 (νT=1) reveal a drag voltage that is equal in magnitude to the drive voltage as soon as the two layers begin to form the expected νT=1 exciton condensate. The identity of both voltages remains present even at elevated temperatures of 0.250.3em0exK. The conductance of the drive layer vanishes only in the limit of strong coupling between the two layers and at T→00.3em0exK which suggests the presence of an excitonic circular current.