Large Enhancement of Critical Current in Superconducting Devices by Gate Voltage

Rocci, Mirko; Suri, Dhavala; Kamra, Akashdeep; Vilela, G. L. S.; Takamura, Yota; Nemes, Norbert M.; Martinez, J.L.; Garcia-Hernandez, M.; Moodera, Jagadeesh S.

doi:10.1021/acs.nanolett.0c03547

Cited by 29 publications

(32 citation statements)

References 53 publications

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“…This electric field-induced quenching of the superconducting state has been observed in different superconducting materials, mostly purely metallic: in titanium transistor-like devices, both in-plane 6 and suspended 7 ; in aluminium nanodevices with a single back-gate 8 or side-gate 9 , deducing from the latter a weak coupling between the electric field and an external magnetic field; in vanadium Dayem nano-bridges, operated as electrical rectifiers 10 ; and in niobium gate-controlled transistors, also exploited as half-wave rectifiers 11 . Uniquely, and contrarily to other works, an enhancement of the critical current with increasing gate voltage has also been observed in niobium nitride thin micro- and nano-bridges, being ascribed to changes in the superconducting vortex surface barrier 12 .…”

Section: Introductionmentioning

confidence: 59%

Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires

Orús

Fomin

Córdoba

2021

Sci Rep

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The critical current of a superconducting nanostructure can be suppressed by applying an electric field in its vicinity. This phenomenon is investigated throughout the fabrication and electrical characterization of superconducting tungsten-carbon (W-C) nanostructures grown by Ga$$^+$$ + focused ion beam induced deposition (FIBID). In a 45 nm-wide, 2.7 $$\upmu $$ μ m-long W-C nanowire, an increasing side-gate voltage is found to progressively reduce the critical current of the device, down to a full suppression of the superconducting state below its critical temperature. This modulation is accounted for by the squeezing of the superconducting current by the electric field within a theoretical model based on the Ginzburg–Landau theory, in agreement with experimental data. Compared to electron beam lithography or sputtering, the single-step FIBID approach provides with enhanced patterning flexibility and yields nanodevices with figures of merit comparable to those retrieved in other superconducting materials, including Ti, Nb, and Al. Exhibiting a higher critical temperature than most of other superconductors, in which this phenomenon has been observed, as well as a reduced critical value of the gate voltage required to fully suppress superconductivity, W-C deposits are strong candidates for the fabrication of nanodevices based on the electric field-induced superconductivity modulation.

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Section: Introductionmentioning

confidence: 59%

Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires

Orús

Fomin

Córdoba

2021

Sci Rep

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“…However, explanations consistent with all the key experimental features and a broad consensus for each material system are still being pursued [23]. Furthermore, the recently observed enhancement in the critical current of type II superconductor NbN films [22] stands out.…”

Section: Introductionmentioning

confidence: 97%

Interfacial control of vortex-limited critical current in type II superconductor films

Hope,

Amundsen,

Suri

et al. 2021

Preprint

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In a class of type II superconductor films, the critical current is determined by the Bean-Livingston barrier posed by the film surfaces to vortex penetration into the sample. A bulk property thus depends sensitively on the surface or interface to an adjacent material. We theoretically investigate the dependence of vortex barrier and critical current in such films on the Rashba spin-orbit coupling at their interfaces with adjacent materials. Considering an interface with a magnetic insulator, we find the spontaneous supercurrent resulting from the Zeeman field and interfacial spin-orbit coupling to substantially modify the vortex surface barrier. Thus, we show that the critical currents in superconductor-magnet heterostructures can be controlled, and even enhanced, via the interfacial spin-orbit coupling. Since the latter can be controlled via a gate voltage, our analysis predicts a class of heterostructures amenable to gate-voltage modulation of superconducting critical currents. It also sheds light on the recently observed gate-voltage enhancement of critical current in NbN superconducting films.

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“…In the last two years, the impact of gate voltage on the superconducting properties of Bardeen-Cooper-Schrieffer (BCS) [1] elemental superconductors has been investigated [2][3][4][5][6][7][8]. In these studies, the authors analyzed the effect of electrostatic gating, generating electric fields reaching the order of 10 8 V/m and, at the same time, creating negligible variations in the surface charge carrier concentration.…”

Section: Introductionmentioning

confidence: 99%

“…In these studies, the authors analyzed the effect of electrostatic gating, generating electric fields reaching the order of 10 8 V/m and, at the same time, creating negligible variations in the surface charge carrier concentration. Although an increase in the critical temperature of a superconducting NbN wire was reported [8], the majority of works in this field show ambipolar suppression of supercurrent, e.g., in all-metallic superconductor wires [2], nano-constriction Josephson junctions (JJs) [3,4], fully metallic Superconducting Quantum Interference Devices (SQUID) [6], and proximity nanojunctions [9]. Such an unconventional gating effect in BCS superconductor systems is the first step in the realization of easy fabrication and high-scalable technologies in both environments of classic superconducting electronics and quantum computing.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, it is not possible to take into account experimental observations through the conventional BCS framework, in which the superconducting properties are negligibly affected by electric fields [10]. Although some theories have been proposed, including surface nucleation and pinning of Abrikosov vortices [8,[11][12][13], the electric fielddriven Rashba orbital polarization [14][15][16][17], and the gate-driven Schwinger excitation of quasiparticles from the BCS vacuum [18][19][20], they have not been experimentally verified yet. The injection of high-energy field-emitted cold-electrons into the weak-link was also hypothesized to be at the origin of the gating effect [21,22].…”

Section: Introductionmentioning

confidence: 99%

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Gate Control of Superconductivity in Mesoscopic All-Metallic Devices

Puglia

Simoni²,

Giazotto³

2021

Materials

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The possibility to tune, through the application of a control gate voltage, the superconducting properties of mesoscopic devices based on Bardeen–Cooper–Schrieffer metals was recently demonstrated. Despite the extensive experimental evidence obtained on different materials and geometries, a description of the microscopic mechanism at the basis of such an unconventional effect has not been provided yet. This work discusses the technological potential of gate control of superconductivity in metallic superconductors and revises the experimental results, which provide information regarding a possible thermal origin of the effect: first, we review experiments performed on high-critical-temperature elemental superconductors (niobium and vanadium) and show how devices based on these materials can be exploited to realize basic electronic tools, such as a half-wave rectifier. Second, we discuss the origin of the gating effect by showing gate-driven suppression of the supercurrent in a suspended titanium wire and by providing a comparison between thermal and electric switching current probability distributions. Furthermore, we discuss the cold field-emission of electrons from the gate employing finite element simulations and compare the results with experimental data. In our view, the presented data provide a strong indication regarding the unlikelihood of the thermal origin of the gating effect.

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Large Enhancement of Critical Current in Superconducting Devices by Gate Voltage

Cited by 29 publications

References 53 publications

Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires

Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires

Interfacial control of vortex-limited critical current in type II superconductor films

Gate Control of Superconductivity in Mesoscopic All-Metallic Devices

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