Single-Cooper-Pair Transistors: Requirements for Robust 2e Periodicity

Published

January 3, 2003

Author(s)

Joe Aumentado, Mark W. Keller, John M. Martinis

Abstract

The superconducting analog of the single-electron transistor (SET), the single-Cooper-pair transistor (SCPT), is comprised of two ultrasmall tunnel junctions in series forming an island (see Figure 1(a)). Transport through the SCPT depends on the electrostatic energy required to charge the island, as in the SET, but also on the Josephson coupling across the junctions. An SCPT was first demonstrated Fulton et al. in 1989, and interest has been renewed with recent work on SCPT-based qubits that have recently demonstrated coherence times on the order of 1 υs. In this paper, we address a long-standing question: What are the practical requirements for obtaining SCPT devices in which coherent transport of Cooper pairs is truly dominant, as required by various applications? We show that a controlled change in the spatial profile of the superconducting energy gap affects this transport dramatically.

Citation

Journal of the Physical Society of Japan

Volume

72

Pub Type

Journals

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Keywords

Cooper pair box, qubits, SET, superconductivity

Citation

Aumentado, J. , Keller, M. and Martinis, J. (2003), Single-Cooper-Pair Transistors: Requirements for Robust 2e Periodicity, Journal of the Physical Society of Japan, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=30757 (Accessed October 9, 2025)