Side gate tunable Josephson junctions at the LaAlO$_3$/SrTiO$_3$ interface

A. M. R. V. L. Monteiro; D. J. Groenendijk; N. Manca; E. Mulazimoglu; S. Goswami; Ya. Blanter; L. M. K. Vandersypen; A. D. Caviglia

doi:10.1021/acs.nanolett.6b03820

arXiv · 1609.03304

Side gate tunable Josephson junctions at the LaAlO$_3$/SrTiO$_3$ interface

A. M. R. V. L. Monteiro·D. J. Groenendijk·N. Manca·E. Mulazimoglu·S. Goswami·Ya. Blanter·L. M. K. Vandersypen·A. D. Caviglia

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Abstract

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$_3$/SrTiO$_3$ 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.

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A. M. R. V. L. Monteiro, D. J. Groenendijk, N. Manca, E. Mulazimoglu, S. Goswami, Ya. Blanter, L. M. K. Vandersypen, A. D. Caviglia. 2016-09-12. Side gate tunable Josephson junctions at the LaAlO$_3$/SrTiO$_3$ interface. https://doi.org/10.1021/acs.nanolett.6b03820

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