Electrical modulation of superconducting critical temperature in liquid-gated thin niobium films

Choi, Joon Sig; Pradheesh, R.; Kim, Hyungsang; Im, Hyunsik; Chong, Yonuk; Chae, Dong-Hun

doi:10.1063/1.4890085

Cited by 32 publications

(27 citation statements)

References 18 publications

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“…4). We note that electric field modulation of superconductivity has been previously demonstrated in metallic thin films [27][28][29]. However, changes of critical temperature by less than one percent required significantly stronger electric fields than those applied here.…”

supporting

confidence: 42%

A superconducting switch actuated by injection of high energy electrons

Ritter,

Fuhrer,

Haxell

et al. 2020

Preprint

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Fast cryogenic switches with ultra-low power dissipation are highly sought-after for control electronics of quantum computers, space applications and next generation logic circuits. However, existing high-frequency switches are often bulky, lossy or require large source-drain and gate currents for operation, making them unsuitable for many applications and difficult to interface to semiconducting devices. Here we present an electrically controlled superconducting switch based on a metallic nanowire. Transition from superconducting to resistive state is realized by tunneling of high-energy electrons from a gate contact through an insulating barrier. Operating gate currents are several orders of magnitude smaller than the nanowire critical source-drain current, effectively resulting in a voltage-controlled device. This superconducting switch is fast, self-resets from normal to superconducting state, and can operate in large magnetic fields, making it an ideal component for low-power cryogenic applications and quantum computing architectures.

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supporting

confidence: 42%

A superconducting switch actuated by injection of high energy electrons

Ritter,

Fuhrer,

Haxell

et al. 2020

Preprint

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“…To better highlight the field distribution, the colour scale was saturated to |E| = 70 MV m −1 . The highest |E| in our simulations was below |E| = 500 MV m −1 , which is several orders of magnitude smaller than typical electric fields required to perturb superconductivity in a metallic device [16][17][18] . Figure 1d shows the experimentally measured I C as a function of V G1 , for temperatures ranging from 20 mK (blue) to 3 K (red).…”

Section: Critical Current Suppression and Electric Fieldsmentioning

confidence: 70%

Out-of-equilibrium phonons in gated superconducting switches

et al. 2022

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Recent experiments have suggested that superconductivity in metallic nanowires can be suppressed by the application of modest gate voltages. The source of this gate action has been debated and either attributed to an electric-field effect or to small leakage currents. Here we show that the suppression of superconductivity in titanium nitride nanowires on silicon substrates does not depend on the presence or absence of an electric field at the nanowire, but requires a current of high-energy electrons. The suppression is most efficient when electrons are injected into the nanowire, but similar results are obtained when electrons are passed between two remote electrodes. This is explained by the decay of high-energy electrons into phonons, which propagate through the substrate and affect superconductivity in the nanowire by generating quasiparticles. By studying the switching probability distribution of the nanowire, we also show that high-energy electron emission leads to a much broader phonon energy distribution compared with the case where superconductivity is suppressed by Joule heating near the nanowire.

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“…The advent of electrolyte gating [7], which relies on the voltage-induced polarization of an electrolyte (which is an ionic conductor and an electronic insulator) between a counter electrode and the sample, allowed to achieve electric fields as large as 10 10 V/m and surface carrier modulations of 10 15 charges cm −2 for gate voltages of the order of a few volts [8]. Therefore, conductivity modulations of about 10% have been demonstrated in metals [9,10], such as gold, copper and silver, and sizable changes of the critical temperature of ∼ 1% in metallic superconductors, such as for niobium [11] and niobium nitride [12], have been achieved. Recent experiments investigated the dependence both of critical current I C and critical temperature of metallic superconductors (aluminum and titanium) on conventional solid gating [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Magnetotransport Experiments on Fully Metallic Superconducting Dayem-Bridge Field-Effect Transistors

Simoni²,

et al. 2019

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In the last 60 years conventional solid and electrolyte gating allowed sizable modulations of the surface carrier concentration in metallic superconductors resulting in tuning their conductivity and changing their critical temperature. Recent conventional gating experiments on superconducting metal nano-structures showed full suppression of the critical current without variations of the normal state resistance and the critical temperature. These results still miss a microscopic explanation. In this article, we show a complete set of gating experiments on Ti-based superconducting Dayem bridges and a suggested classical thermodynamic model which seems to account for several of our experimental findings. In particular, zero-bias resistance and critical current IC measurements highlight the following: the suppression of IC with both polarities of gate voltage, the surface nature of the effect, the critical temperature independence from the electric field and the gate-induced growth of a sub-gap dissipative component. In addition, the temperature dependence of the Josephson critical current seems to show the transition from the ballistic Kulik-Omelyanchuck behavior to the Ambegaokar-Baratoff tunnel-like characteristic by increasing the electric field. Furthermore, the IC suppression persists in the presence of sizeable perpendicular-to-plane magnetic fields. We propose a classical thermodynamic model able to describe some of the experimental observations of the present and previous works. Above all, the model grabs the bipolar electric field induced suppression of IC and the emergence of a sub-gap dissipative component near full suppression of the supercurrent. Finally, applications employing the discussed effect are proposed.

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Electrical modulation of superconducting critical temperature in liquid-gated thin niobium films

Cited by 32 publications

References 18 publications

A superconducting switch actuated by injection of high energy electrons

A superconducting switch actuated by injection of high energy electrons

Out-of-equilibrium phonons in gated superconducting switches

Magnetotransport Experiments on Fully Metallic Superconducting Dayem-Bridge Field-Effect Transistors

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