Fabry-Perot Interferometry with Fractional Charges

Resistance oscillations in electronic Fabry-Perot interferometers near fractional quantum Hall (FQH) filling factors 1/3, 2/3, 4/3 and 5/3 in the constrictions are compared to corresponding oscillations near integer quantum Hall (IQH) filling factors in the constrictions, appearing in the same devices and at the same gate voltages. Two-dimensional plots of resistance versus gate voltage and magnetic field indicate that all oscillations are Coulomb dominated. Applying a Coulomb charging model yields an effective tunneling charge e* \approx e/3 for all FQH constrictions and e* \approx e for IQH constrictions. Surprisingly, we find a common characteristic temperature for FQH oscillations and a different common characteristic temperature for IQH oscillations.