Area dependence of interlayer tunneling in strongly correlated bilayer two-dimensional electron systems at ν_T=1

The area and perimeter dependences of the Josephson-like interlayer tunneling signature of the coherent ν_T=1 quantum Hall phase in bilayer two-dimensional electron systems is examined. Electrostatic top gates of various sizes and shapes are used to locally define distinct ν_T=1 regions in the same sample. Near the phase boundary with the incoherent ν_T=1 state at large layer separation, our results demonstrate that the tunneling conductance in the coherent phase is closely proportional to the total area of the tunneling region. This implies that tunneling at ν_T=1 is a bulk phenomenon in this regime.