Vortex-Antivortex Pair Dissociation in Two-Dimensional Superconductors

Epstein, K.; Goldman, A. M.; Kadin, Alan M.

doi:10.1103/physrevlett.47.534

Cited by 164 publications

(90 citation statements)

References 14 publications

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“…Many previous studies of the SN transition in 2-D were scaling analyses of nonlinear dc current-voltage (I-V) characteristics, [6][7][8][9][10] and thus cannot be compared directly with ours. While these papers generally acknowledge good agreement with KTB theory, Pierson et al [11] have revisited the scaling analyses of many I-V measurements, as well as dynamic measurements on 2-D He films, and they find that when the dynamical exponent, z, is taken to be an adjustable parameter, the best scaling occurs for z = 5.6 ± 0.3, not the KTB value, z = 2.…”

Section: Introductionmentioning

confidence: 91%

Dynamic impedance of two-dimensional superconducting films near the superconducting transition

2001

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The sheet impedances, Z(ω,T), of several superconducting a-Mo 77 Ge 23 films and one In/InO x film have been measured in zero field using a two-coil mutual inductance technique at frequencies from 100 Hz to 100 kHz. Z(ω,T) is found to have three contributions: the inductive superfluid, renormalized by nonvortex phase fluctuations; conventional vortex-antivortex pairs, whose contribution turns on very rapidly just below the usual Kosterlitz-Thouless-Berezinskii unbinding temperature; and an anomalous contribution. The latter is predominantly resistive, persists well below the KTB temperature, and is weakly dependent on frequency down to remarkably low frequencies, at least 100 Hz. It increases with T as e -U'(T)/kT , where the activation energy, U'(T), is about half the energy to create a vortex-antivortex pair, indicating that the frequency dependence is that of individual excitations, rather than critical behavior.

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Section: Introductionmentioning

confidence: 91%

Dynamic impedance of two-dimensional superconducting films near the superconducting transition

2001

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“…In the presence of current flow, local areas of strong superconductivity could become decoupled from each other, thus permitting local phase fluctuations. Another scenario may involve the proliferation of thermally-generated vortex-antivortex pairs in the Kosterlitz-Thouless picture 22,23 , but with current as an additional driving force 24,25 . In principle, the static phase gradient carried by the supercurrent could also couple dynamically with other types of phase-ordered states, such as spin/charge-density waves 26,27 , staggered flux-like states 28,29,30 or collective modes 31,32 , to produce enhanced phase fluctuations.…”

Section: Discussionmentioning

confidence: 99%

Suppression of low-energy Andreev states by a supercurrent inYBa2Cu3O7−δ

2005

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We report a coherence-length scale phenomenon related to how the high-Tc order parameter (OP) evolves under a directly-applied supercurrent. Scanning tunneling spectroscopy was performed on current-carrying YBa2Cu3O 7−δ thin-film strips at 4.2K. At current levels well below the theoretical depairing limit, the low-energy Andreev states are suppressed by the supercurrent, while the gap-like structures remain unchanged. We rule out the likelihood of various extrinsic effects, and propose instead a model based on phase fluctuations in the d -wave BTK formalism to explain the suppression. Our results suggest that a supercurrent could weaken the local phase coherence while preserving the pairing amplitude. Other possible scenarios which may cause the observed phenomenon are also discussed.

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“…For a 2D system, it is well established that the superconducting transition should obey a BKT transition, characterized by a transition temperature T BKT . [31][32][33][34][35][36] Below T BKT , vortices and antivortices pairs are formed, and the zero-resistance state appears. As temperature rising, a thermodynamic instability should occur in which vortex-antivortex pairs, bound at low temperatures, spontaneously unbind into free vortices at the characteristic transition temperature T BKT , and the proliferation of free vortices destroys superconductivity.…”

Section: Resultsmentioning

confidence: 99%

“…As temperature rising, a thermodynamic instability should occur in which vortex-antivortex pairs, bound at low temperatures, spontaneously unbind into free vortices at the characteristic transition temperature T BKT , and the proliferation of free vortices destroys superconductivity. According to the BKT transition theory, near the T BKT , (I) a strong non-Ohmic behavior in the V-I characteristics displays, in a simple power law with a = 3 at T BKT ; 32,35,37 Therefore, in order to examine the 2D superconductive characteristics of our 5-uc (110) LAO/STO heterojunction samples, we measured the V-I characteristics from 50 mK, where the samples are completely superconductive, to higher temperature where the samples recover to normal state. The representative results of a sample same to that of Fig.…”

Section: Resultsmentioning

confidence: 99%

Two-dimensional superconductivity at (110) LaAlO3/SrTiO3 interfaces

Han

Shen

You

et al. 2014

Applied Physics Letters

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Novel low dimensional quantum phenomena are expected at (110) LaAlO 3 /SrTiO 3 (LAO/STO) interfaces after the quasi two dimensional electron gas similar to that of (001) LAO/STO interfaces was found [G. Herranz et al., Sci. Rep. 2, 758 (2012) and A. Annadi et al., Nat. Commun. 4, 1838]. Here, two dimensional superconductivity of (110) LAO/STO samples with a superconducting transition temperature of 184 mK is demonstrated based on systematical transport measurements. The two dimensional characteristic of the superconductivity is confirmed by analyzing the Berezinskii-Kosterlitz-Thouless transition. The estimated superconductive thickness is about 18 nm. These features of superconductivity of (110) LAO/STO interfaces are comparable to those of (001) LAO/STO interfaces. This discovery may inspire a new round of upsurge on study of LAO/STO interfaces.

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Vortex-Antivortex Pair Dissociation in Two-Dimensional Superconductors

Cited by 164 publications

References 14 publications

Dynamic impedance of two-dimensional superconducting films near the superconducting transition

Dynamic impedance of two-dimensional superconducting films near the superconducting transition

Suppression of low-energy Andreev states by a supercurrent inYBa2Cu3O7−δ

Two-dimensional superconductivity at (110) LaAlO3/SrTiO3 interfaces

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