SQUIPT - Superconducting Quantum Interference Proximity Transistor
SQUIPT - Superconducting Quantum Interference Proximity Transistor
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SQUIPT - 超导量子干涉接近晶体管
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Pekola
中科院分区：
文献类型：
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作者：
F. Giazotto;J. Peltonen;Matthias Meschke;J. Pekola
基于约瑟夫森效应的超导量子干涉器件的发展使我们测量磁场的能力得到了显著的提高。一种类似的设备，被称为超导量子干涉晶体管，它利用邻近效应，可以允许类似的重大进一步改进。当超导体靠近非超导金属放置时，它可以在金属1，2，3，4，5，6，7，8，9，10中诱导超导相关性，称为“邻近效应”11。这种行为改变了正常金属12，13，14，15中的态密度（DOS），并打开了一个小间隙12，13，16，其幅度可以通过改变超导序参量12，15的相位来控制。在这里，我们利用这种行为来实现一种新型的干涉仪，超导量子干涉邻近晶体管（SQUIPT），其操作依赖于嵌入在超导回路中的邻近金属的DOS的磁场的调制。即使没有优化其设计，该器件也显示出极低的磁通噪声，低至10−5 Φ 0 Hz −1/2（Φ0 − 2×10−15 Wb是磁通量子），并且耗散比传统的超导干涉仪小几个数量级17，18，19。通过优化，SQUIPT可以显着提高检测小磁矩的灵敏度。
The development of superconducting quantum interference devices based on the Josephson effect has led to significant improvements in our ability to measure magnetic fields. A similar device, dubbed the superconducting quantum interference transistor, which exploits the proximity effect, could allow similar significant further improvements. When a superconductor is placed close to a non-superconducting metal, it can induce superconducting correlations in the metal 1,2,3,4,5,6,7,8,9,10, known as the ‘proximity effect’11. Such behaviour modifies the density of states (DOS) in the normal metal12,13,14,15 and opens a minigap12,13,16 with an amplitude that can be controlled by changing the phase of the superconducting order parameter12,15. Here, we exploit such behaviour to realize a new type of interferometer, the superconducting quantum interference proximity transistor (SQUIPT), for which the operation relies on the modulation with the magnetic field of the DOS of a proximized metal embedded in a superconducting loop. Even without optimizing its design, this device shows extremely low flux noise, down to ∼10−5 Φ0Hz−1/2 (Φ0≃2×10−15 Wb is the flux quantum) and dissipation several orders of magnitude smaller than in conventional superconducting interferometers17,18,19. With optimization, the SQUIPT could significantly increase the sensitivity with which small magnetic moments are detected.