Bidirectional Counting of Single Electrons

A bidirectional single-electron counting device is demonstrated.

Key Results

Individual electrons flowing in forward and reverse directions through a double quantum dot are detected with a quantum point contact acting as a charge sensor.
A comprehensive statistical analysis in the frequency and time domains and of higher order moments of noise reveals antibunching correlation in single-electron transport through the device itself.
The device can also be used to investigate current flow in the attoampere range, which cannot be measured by existing current meters.