Superconducting pair-breaking under intense sub-gap terahertz radiation

Tian, Jie; Zuber, Jack; Huang, Sunchao; Zhang, Chaofeng

doi:10.1063/1.5098045

Cited by 3 publications

(3 citation statements)

References 24 publications

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“…Antisymmetric SOI, Rashba and Zeeman SOI, and thus the corresponding spin-splitting can be tuned via electric field. Superconducting pair-breaking shows strong dependence on the strength and the frequency/wavelength of electric field [179]. Similarly, it is shown that a gate tunable critical current in a NbN micro-and nano superconducting bridges [180] can be enhanced up to 30%.…”

Section: Discussionmentioning

confidence: 88%

Superconducting Diode Effect -- Fundamental Concepts, Material Aspects, and Device Prospects

Nadeem¹,

Fuhrer²,

Wang³

2023

Preprint

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Superconducting diode effect, in analogy to the nonreciprocal resistive charge transport in semiconducting diode, is a nonreciprocity of dissipationless supercurrent. Such an exotic phenomenon originates from intertwining between symmetry-constrained supercurrent transport and intrinsic quantum functionalities of helical/chiral superconductors. In this article, research progress of superconducting diode effect including fundamental concepts, material aspects, device prospects, and theoretical/experimental development is reviewed. First, fundamental mechanisms to cause superconducting diode effect including simultaneous space-inversion and time-reversal symmetry breaking, magnetochiral anisotropy, interplay between spin-orbit interaction energy and the characteristic energy scale of supercurrent carriers, and finite-momentum Cooper pairing are discussed. Second, the progress of superconducting diode effect from theoretical predictions to experimental observations are reviewed. Third, interplay between various system parameters leading to superconducting diode effect with optimal performance is presented. Then, it is explicitly highlighted that nonreciprocity of supercurrent can be characterized either by current-voltage relation obtained from resistive directcurrent measurements in the metal-superconductor fluctuation region (T ≈ Tc) or by current-phase relation and nonreciprocity of superfluid inductance obtained from alternating-current measurements in the superconducting phase (T < Tc). Finally, insight into future directions in this active research field is provided with a perspective analysis on intertwining between band-topology and helical superconductivity, which could be useful to steer the engineering of emergent topological superconducting technologies.

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Section: Discussionmentioning

confidence: 88%

Superconducting Diode Effect -- Fundamental Concepts, Material Aspects, and Device Prospects

Nadeem¹,

Fuhrer²,

Wang³

2023

Preprint

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“…Charge redistribution and electric polarization can create local electric fields that interact with the qubits, leading to fluctuations in the qubit energy levels and causing decoherence. These fluctuations can cause quasiparticle loss on the surface of the superconducting film . In the presence of the local electric field, electrons within the Cooper pair can experience an energy imbalance, leading to the breakup of the pairs, so-called pair breaking.…”

Section: Discussion and Computational Interpretationmentioning

confidence: 99%

“…These fluctuations can cause quasiparticle loss on the surface of the superconducting film. 53 In the presence of the local electric field, electrons within the Cooper pair can experience an energy imbalance, leading to the breakup of the pairs, so-called pair breaking. The electric field can increase the probability of pair breaking, leading to qubit decoherence.…”

Section: Discussion and Computational Interpretationmentioning

confidence: 99%

Probing Oxidation-Driven Amorphized Surfaces in a Ta(110) Film for Superconducting Qubit

Mun,

Sushko,

Brass

et al. 2023

ACS Nano

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Recent advances in superconducting qubit technology have led to significant progress in quantum computing, but the challenge of achieving a long coherence time remains. Despite the excellent lifetime performance that tantalum (Ta) based qubits have demonstrated to date, the majority of superconducting qubit systems, including Ta-based qubits, are generally believed to have uncontrolled surface oxidation as the primary source of the two-level system loss in two-dimensional transmon qubits. Therefore, atomic-scale insight into the surface oxidation process is needed to make progress toward a practical quantum processor. In this study, the surface oxidation mechanism of native Ta films and its potential impact on the lifetime of superconducting qubits were investigated using advanced scanning transmission electron microscopy (STEM) techniques combined with density functional theory calculations. The results suggest an atomistic model of the oxidized Ta(110) surface, showing that oxygen atoms tend to penetrate the Ta surface and accumulate between the two outermost Ta atomic planes; oxygen accumulation at the level exceeding a 1:1 O/Ta ratio drives disordering and, eventually, the formation of an amorphous Ta 2 O 5 phase. In addition, we discuss how the formation of a noninsulating ordered TaO 1−δ (δ < 0.1) suboxide layer could further contribute to the losses of superconducting qubits. Subsurface oxidation leads to charge redistribution and electric polarization, potentially causing quasiparticle loss and decreased current-carrying capacity, thus affecting superconducting qubit coherence. The findings enhance the comprehension of the realistic factors that might influence the performance of superconducting qubits, thus providing valuable guidance for the development of future quantum computing hardware.

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