Study on Single-Electron Transistor controlled by Environmental Impedance

点击翻译按钮获取中文摘要

In order to discuss the effects of environmental impedance on Coulomb blockade, we established a basic theory in which we can calculate transport properties of a single-electron transistor (SET) with arbitrary environmental impedance. We calculated numerically transport properties of SETs self-consistently and showed that SETs can be controlled by environmental impedance modulation. Moreover, we estimated the maximum parasitic capacitance, because environmental impedance becomes low due to parasitic capacitance in actual devices.We fabricated SETs controlled by environmental impedance modulation, using a GaAs/AlGaAs heterostructure and electron-beam lithography technique and measured transport properties at low temperature. We succeeded in controlling actually the transport properties by modulating the environmental impedance.We also fabricated SETs with different parasitic capacitance and showed that SET can not be controlled when the capacitance becomes large.We established a theory for three-terminal devices in which all charges and environmental impedances were treated quantum mechanically. Using the theory, we discussed charge fluctuations and asymmetric environment effects.Controlling charge fluctuations is quite important in single electronics because SETs are severely affected by charge fluctuation.