Monteiro A M R V L, Groenendijk D J, Manca N, Mulazimoglu E, Goswami S, Blanter Ya, Vandersypen L M K, Caviglia A D
Kavli Institute of Nanoscience, Delft University of Technology , P.O. Box 5046, 2600 GA Delft, Netherlands.
Nano Lett. 2017 Feb 8;17(2):715-720. doi: 10.1021/acs.nanolett.6b03820. Epub 2017 Jan 19.
Novel physical phenomena arising at the interface of complex oxide heterostructures offer exciting opportunities for the development of future electronic devices. Using the prototypical LaAlO/SrTiO interface as a model system, we employ a single-step lithographic process to realize gate-tunable Josephson junctions through a combination of lateral confinement and local side gating. The action of the side gates is found to be comparable to that of a local back gate, constituting a robust and efficient way to control the properties of the interface at the nanoscale. We demonstrate that the side gates enable reliable tuning of both the normal-state resistance and the critical (Josephson) current of the constrictions. The conductance and Josephson current show mesoscopic fluctuations as a function of the applied side gate voltage, and the analysis of their amplitude enables the extraction of the phase coherence and thermal lengths. Finally, we realize a superconducting quantum interference device in which the critical currents of each of the constriction-type Josephson junctions can be controlled independently via the side gates.
复杂氧化物异质结构界面处出现的新型物理现象为未来电子器件的发展提供了令人兴奋的机遇。我们以典型的LaAlO/SrTiO界面作为模型系统，采用单步光刻工艺，通过横向限制和局部侧栅极相结合的方式实现栅极可调谐约瑟夫森结。发现侧栅极的作用与局部背栅极相当，这是一种在纳米尺度上控制界面特性的稳健且有效的方法。我们证明，侧栅极能够可靠地调节缩颈的正常态电阻和临界（约瑟夫森）电流。电导和约瑟夫森电流随施加的侧栅极电压呈现介观涨落，对其幅度的分析能够提取相位相干长度和热长度。最后，我们实现了一种超导量子干涉器件，其中每个缩颈型约瑟夫森结的临界电流都可以通过侧栅极独立控制。
