Gate voltage dependence of a single-electron transistor using the shuttle mechanism

Abstract

The gate voltage dependence of a single-electron transistor using the shuttle mechanism in which a vibrating conductive nanoparticle carries charges between the electrodes is studied theoretically and with numerical simulations. Two types of gate voltage effect on the transport properties are demonstrated: one is direct modulation of the current via modification in the tunneling rate, giving rise to shift of ] I/]V peaks on the step-like current, splitting of the current steps and periodic behavior of the current with the change in gate voltage. Another is an indirect effect due to a shift in the range of the nanoparticle vibration induced by the gate voltage. The latter effect stops the shuttle mechanism at a large gate voltage, leading to the conduction gap which widens in proportion to the gate voltage

Low-frequency current noise of the single-electron shuttle

“…Since current through the system is accompanied by charging of the grain, interplay between the Coulomb forces and the mechanical degrees of freedom can lead to self-oscillations of the grain, which in turn, supports charge transport through shuttling of electrons between the leads. Much work, both experimental [5,6,7,8,9] as well as theoretical [4,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24] has been reported in this field.…”

Shuttle instability induced by an ac gate in a nanoelectromechanical single-electron transistor

“…We found in a previous work 9 that a large dc gate voltage halts the grain vibrations of the NEM-SET and then the dominant transport mechanism changes from shuttling to tunneling. The shuttle mechanism reversibly recovers after turning off the dc gate.…”

“…͑26͒ even if E is very small, in contrast to the NEM-SET in the absence of the ac gate, 7,9 in which W͑E͒ is expanded in a power series of E. The vibrational energy satisfying Eq. ͑26͒ yields…”

Observation of Coulomb staircases of both tunneling current and displacement current in nanomechanical double barrier tunneling structures

“…[1][2][3][4][5][6] In electron shuttle devices, the electrons on the vibrating conductive nanoparticles are quantized by Coulomb blockade, and can be transported using the shuttle mechanism in which vibrating conductive nanoparticles carry electrons between the reservoirs, since the nanomechanics for vibrating the nanoparticle have been combined into electronics. 3,5,6 For the study and realization of nanomechanical single-electron devices, such as the electron shuttle, the detection technique for investigating the motion of the single electrons would be important. One of the useful techniques would be measurement of the displacement current, since the displacement current flows due to a time-dependent change in the charge, structure, potential, and so on.…”