Decay of Persistent Currents in Small Superconductors

Little, W. A.

doi:10.1103/physrev.156.396

Cited by 280 publications

(206 citation statements)

References 16 publications

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“…Since the length of Mo 76 Ge 24 nanowires is sufficiently longer than ξ (0) and √σ <4.4ξ, these wires are in a quasi one-dimensional long wire limit [ 11,20,21 ].…”

Section: Figure 2 (A) R (T) Curves Of Twomentioning

confidence: 99%

Current-Phase Relationship, Thermal and Quantum Phase Slips in Superconducting Nanowires Made on a Scaffold Created Using Adhesive Tape

et al. 2009

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Quantum phase slippage (QPS) in a superconducting nanowire is a new candidate for developing a quantum bit [ 1 , 2 ]. It has also been theoretically predicted that the occurrence of QPS significantly changes the current-phase relationship (CPR) of the wire due to the tunneling between topologically different metastable states [ 3 ]. We present studies on the microwave response of the superconducting nanowires to reveal their CPRs. First, we demonstrate a simple nanowire fabrication technique, based on commercially available adhesive tapes, which allows making thin superconducting wire from different metals. We compare the resistance vs. temperature curves of Mo 76 Ge 24 and Al nanowires to the classical and quantum models of phase slips. In order to describe the experimentally observed microwave responses of these nanowires, we use the McCumber-Stewart model [ 4 ], which is generalized to include either classical or quantum CPR.

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“…Since the length of Mo 76 Ge 24 nanowires is sufficiently longer than ξ (0) and √σ <4.4ξ, these wires are in a quasi one-dimensional long wire limit [ 11,20,21 ].…”

Section: Figure 2 (A) R (T) Curves Of Twomentioning

confidence: 99%

Current-Phase Relationship, Thermal and Quantum Phase Slips in Superconducting Nanowires Made on a Scaffold Created Using Adhesive Tape

et al. 2009

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“…Both the temperature and the magnetic field dependencies of the diamagnetic signal displayed a smooth variation, owing to the fluctuation effect 15 (see Appendix B), whereby finite resistance can be generated by thermally activated phase slips as predicted by the LAMH theory [43][44][45] (see Appendix C). Fig.…”

Section: Quasi One Dimensional Fluctuation Superconductivitymentioning

confidence: 99%

“…The smooth resistance variations as a function of temperature/bias current manifestations are consistent with the expected quasi 1D superconductivity behaviors, and they can be interpreted within the framework of thermally activated phase slips as formulated by the LAMH theory. [43][44][45] In this formulation, the wave function j ¼ |j|exp (i4) of a superconducting element is regarded to be constant across the cross sectional area (since the cross sectional dimension is smaller than the coherence length) and varies only as a function of x along the c-axis. For a fixed temperature, the magnitude |j| is rather rigid and only the phase can change as a function of x.…”

Section: Quasi One Dimensional Fluctuation Superconductivitymentioning

confidence: 99%

Superconductivity in 4-Angstrom carbon nanotubes—a short review

et al. 2012

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We give an up-to-date review of the superconducting phenomena in 4-Angstrom carbon nanotubes embedded in aligned linear pores of the AlPO 4 -5 (AFI) zeolite, first discovered in 2001 as a fluctuation Meissner effect. With the introduction of a new approach to sample synthesis around 2007, new data confirming the superconductivity have been obtained. These comprise electrical, specific heat, and magnetic measurements which together yield a consistent yet complex physical picture of the superconducting state, largely owing to the one-dimensional (1D) nature of the 4-Angstrom carbon nanotubes. For the electrical transport characteristics, two types of superconducting resistive behaviors were reproducibly observed in different samples. The first type is the quasi 1D fluctuation superconductivity that exhibits a smooth resistance drop with decreasing temperature, initiating at 15 K. At low temperatures the differential resistance also shows a smooth increase with increasing bias current (voltage). Both are unaffected by an applied magnetic field up to 11 Tesla. These manifestations are shown to be consistent with those of a quasi 1D superconductor with thermally activated phase slips as predicted by the Langer-Ambegaokar-McCumber-Halperin (LAMH) theory. The second type is the quasi 1D to 3D superconducting crossover transition, which was observed to initiate at 15 K with a slow resistance decrease switching to a sharp order of magnitude drop at $7.5 K. The latter exhibits anisotropic magnetic field dependence and is attributed to a Berezinskii-Kosterlitz-Thouless (BKT)-like transition that establishes quasi-long-range order in the plane transverse to the c-axis of the aligned nanotubes, thereby mediating a 1D to 3D crossover. The electrical data are complemented by magnetic and thermal specific heat bulk measurements. By using both the SQUID VSM and the magnetic torque technique, the onset of diamagnetism was observed to occur at $15 K, with a rapid increase of the diamagnetic moment below $7 K. The zero-field-cooled and field-cooled branches deviated from each other below 7 K, indicating the establishment of a 3D Meissner state with macroscopic phase coherence. The superconductivity is further supported by the specific heat measurements, which show an anomaly with onset at 15 K and a peak at 11-12 K. In the 3D superconducting state, the nanotube arrays constitute a type-II anisotropic superconductor with H c1 z 60 to 150 Oe, coherence length x z 5 to 15 nm, London penetration length l z 1.5 mm, and Ginzburg-Landau k z 100. We give a physical interpretation to the observed phenomena and note the challenges and prospects ahead.

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“…This suppression of the transport might be interpreted as a consequence of stronger effects of thermal and quantum fluctuations in 1D. At temperatures higher than a certain characteristic value, thermal fluctuations allow the amplitude of the superfluid order parameter to vanish and its phase to unwind, leading to the decay of superflow [12][13][14]. Such a process is often referred to as a phase slip.…”

Section: Introductionmentioning

confidence: 99%

Quantum phase slips in one-dimensional superfluids in a periodic potential

Danshita

Polkovnikov

2012

Phys. Rev. A

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We study the decay of superflow of a one-dimensional (1D) superfluid in the presence of a periodic potential. In 1D, superflow at zero temperature can decay via quantum nucleation of phase slips even when the flow velocity is much smaller than the critical velocity predicted by mean-field theories. Applying the instanton method to the O(2) quantum rotor model, we calculate the nucleation rate of quantum phase slips Γ. When the flow momentum p is small, we find that the nucleation rate per unit length increases algebraically with p as Γ/L ∝ p 2K−2 , where L is the system size and K is the Tomonaga-Luttinger parameter. Based on the relation between the nucleation rate and the quantum superfluid-insulator transition, we present a unified explanation on the scaling formulae of the nucleation rate for periodic, disorder, and single-barrier potentials. Using the time-evolving block decimation method, we compute the exact quantum dynamics of the superflow decay in the 1D Bose-Hubbard model at unit filling. From the numerical analyses, we show that the scaling formula is valid for the case of the Bose-Hubbard model, which can quantitatively describe Bose gases in optical lattices.

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Decay of Persistent Currents in Small Superconductors

Cited by 280 publications

References 16 publications

Current-Phase Relationship, Thermal and Quantum Phase Slips in Superconducting Nanowires Made on a Scaffold Created Using Adhesive Tape

Current-Phase Relationship, Thermal and Quantum Phase Slips in Superconducting Nanowires Made on a Scaffold Created Using Adhesive Tape

Superconductivity in 4-Angstrom carbon nanotubes—a short review

Quantum phase slips in one-dimensional superfluids in a periodic potential

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