Edge-edge coupling drives period-halving in Fabry-P\'erot interferometers in the integer quantum Hall regime

Electronic Fabry-P\'erot interferometers operated in the quantum Hall regime facilitate study of coherent charge transport and interactions between localized charges and propagating edge modes. Experimental observations of flux periodicity $\phi_{0}/2$, where $\phi_0=h/e$ is the magnetic flux quantum, in the integer quantum Hall regime have recently been attributed to an exotic electron pairing mechanism. We present measurements of a AlGaAs/GaAs Fabry-P\'erot interferometer operated in the integer quantum Hall regime at filling factors $1\leq \nu \leq 3$ that has been designed to express moderate bulk-edge and edge-edge coupling. Under specific conditions at integer fillings, we observe oscillations with flux periodicity $\phi_{0}/2$ for the outermost mode. However, our data and analysis indicate that period-halving is not driven by electron pairing, but rather, is the result of electrostatic coupling between multiple independent edge modes.