Sensitive current measurement on a quantum antidot with a Corbino-Type electrode

Abstract

Quantum antidots (QAD), which are a potential energy hill in a quantum Hall state, offer an ideal test-bed to study bound states in quantum Hall states. So far, electron transport in QAD devices has been investigated mostly by measuring the voltage between voltage probes, which, however, may not be suitable to detect small current on the order of pico-Amperes or less. Here, we utilize a Corbino-Type electrode to directly measure the current through the QADs. We find the direct current measurement with a current-voltage converter provides a more precise tunneling current than the voltage measurement with a voltage amplifier.