Simulation method of transmission-type Radio-Frequency Single-Electron Transistor (RF-SET) by SPICE

An efficient simulation method for transmission-type radio-frequency single-electron transistors (RF-SETs) is developed. By introducing equivalent circuits of propagating microwaves through RF cables, we solve the master equation for RF-SETs self-consistently by using the conventional circuit simulator SPICE including the SET current model. By examining transmitted waves from the transmission-type RFSET, we show that the developed method successfully reproduces the numerical reference methods (calculated self-consistently). We also show that our method provides simple and fast ways to simulate the RF-SETs even under complicated circuit geometry and in high frequencies over GHz.

I. Introduction

The single-electron transistor (SET) [1] is known as a highly sensitive electrometer in measuring quantum states of quantum computations because it allows fractions of one electron on a small metallic island (Quantum dot) to be detected [2], [3]. However, the conventional SET has suffered from its relatively large output resistance. The corresponding RC time-constant limits its bandwidth to a few kHz due to its typical resistance value of and the typical cable capacitance value of 1 nF. The radio-frequency single-electron transistor (RF-SET) consisting of a tank (LC) circuit and an SET has been developed to increase the bandwidth, which is based on the microwave reflected and transmitted from the tank circuit [2], [3]. The tank circuit works as the impedance transformer providing a better match between effective SET differential resistance and microwave cable impedance (typically ), To design tank circuits and to analyze its response and sensitivity of charges, various simulation methods for the RF-SET have been developed [4]–[6]. However, simulation methods of a reflection-type RF-SET have been reported and no simulation methods of transmission-type RF-SET have been developed. In this abstract, we introduce an efficient simulation method for transmission-type RF-SET. The SET model in a transmission-type RF-SET are based on a time-dependant model which may give rise to more accuracy than a steady-state one in high frequency regime [6], [7].