AWhat changed
Lafarge and colleagues monitored a metallic island connected to a reservoir through four tunnel junctions. A coupled single-electron-transistor electrometer resolved discrete potential jumps as individual electrons entered or left the island, with charge remaining fixed between resolved events. Gate sweeps produced a hysteretic charge staircase. The measured switching rate greatly exceeded the simple cotunnelling prediction, exposing a limitation relevant to proposed precision charge-transfer devices.
Scientific scope
Lafarge and colleagues monitored a metallic island connected to a reservoir through four tunnel junctions. A coupled single-electron-transistor electrometer resolved discrete potential jumps as individual electrons entered or left the island, with charge remaining fixed between resolved events. Gate sweeps produced a hysteretic charge staircase. The measured switching rate greatly exceeded the simple cotunnelling prediction, exposing a limitation relevant to proposed precision charge-transfer devices. The observations concern a cryogenic device, calibrated charge increments and finite measurement bandwidth. They do not establish a new value of the elementary charge, error-free pumping or a universal metrological limit. The origin of the excess switching rate remained unresolved; superconducting measurements showed single-electron rather than two-electron jumps. The cited 1992 author manuscript is reproduced in a 1993 thesis.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The observations concern a cryogenic device, calibrated charge increments and finite measurement bandwidth. They do not establish a new value of the elementary charge, error-free pumping or a universal metrological limit. The origin of the excess switching rate remained unresolved; superconducting measurements showed single-electron rather than two-electron jumps. The cited 1992 author manuscript is reproduced in a 1993 thesis.
Contributors
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