Coulomb oscillations of a quantum antidot formed by an airbridged pillar gate in the integer and fractional quantum Hall regime

Quantum antidots (QAD) are attractive for manipulating quasiparticles in quantum Hall (QH) systems. Here, we form a QAD in the integer and fractional QH regimes at nominal Landau-level filling factor ν̅= 2, 1, and 2/3 using a submicron pillar gate with an airbridge connection. After confirming the required conditions for a fully depleted QAD, we analyze the observed Coulomb oscillations in terms of the area of the QAD and the effective charge for the oscillation period in an identical gate voltage range. The area at ν̅= 2/3 is significantly smaller than that at ν̅= 2 and 1, in qualitative agreement with the previous report. By assuming a constant gate capacitance, the effective charge at ν̅= 2/3 is about 2/3 of that at ν̅= 2 and 1. The QAD device can be used to capture and emit charges in the unit of 2e/3.