Search results for "Single-electron"
showing 5 items of 5 documents
Memory effects in single-electron nanostructures
2001
We investigate the memory function at room temperature in devices based on quantum dots. By Low Pressure Chemical Vapour Deposition (LPCVD) we deposited Si dots embedded in SiO2. On these devices flat band voltage shifts were well detected at low write voltages for write times of the order of milliseconds, and furthermore, a plateau in the flat band voltage shift, maybe consequence of Coulomb blockdale, was observed.
Gigahertz Single-Electron Pumping Mediated by Parasitic States
2018
In quantum metrology, semiconductor single-electron pumps are used to generate accurate electric currents with the ultimate goal of implementing the emerging quantum standard of the ampere. Pumps based on electrostatically defined tunable quantum dots (QDs) have thus far shown the most promising performance in combining fast and accurate charge transfer. However, at frequencies exceeding approximately 1 GHz, the accuracy typically decreases. Recently, hybrid pumps based on QDs coupled to trap states have led to increased transfer rates due to tighter electrostatic confinement. Here, we operate a hybrid electron pump in silicon obtained by coupling a QD to multiple parasitic states, and achi…
Measuring charge based quantum bits by a superconducting single-electron transistor
2002
Single-electron transistors have been proposed to be used as a read-out device for Cooper pair charge qubits. Here we show that a coupled superconducting transistor at a threshold voltage is much more effective in measuring the state of a qubit than a normal-metal transistor at the same voltage range. The effect of the superconducting gap is to completely block the current through the transistor when the qubit is in the logical state 1, compared to the mere diminishment of the current in the normal-metal case. The time evolution of the system is solved when the measuring device is driven out of equilibrium and the setting is analysed numerically for parameters accessible by lithographic alu…
Feasibility of Coulomb blockade thermometry in metrology
2000
Abstract Coulomb blockade thermometer (CBT) is a simple, magnetic-field-independent primary thermometer for everyday use at cryogenic temperatures. Its properties are well understood by now. The absolute accuracy at present is about ±0.5%. Recently, we have started studying the possibility of using CBT in metrological applications. We have especially in mind the future extension of the international temperature scale below 0.65 K, which is the lower end of ITS-90. Experiments with arrays containing more than 100 tunnel junctions in series are in progress in order to decrease the effects of electromagnetic environment and of co-tunnelling even below the present level.
Time-energy filtering of single electrons in ballistic waveguides
2019
Characterizing distinct electron wave packets is a basic task for solid-state electron quantum optics with applications in quantum metrology and sensing. A important circuit element for this task is a non-stationary potential barrier than enables backscattering of chiral particles depending on their energy and time of arrival. Here we solve the quantum mechanical problem of single-particle scattering by a ballistic constriction in an fully depleted quantum Hall system under spatially uniform but time-dependent electrostatic potential modulation. The result describes electrons distributed in time-energy space according to a modified Wigner quasiprobability distribution and scattered with an …