Current-driven vortex dynamics in untwinned superconducting single crystals

Jiang, W.; Yeh, N.-C.; Tombrello, T. A.; Rice, Ashley; Holtzberg, F.

doi:10.1088/0953-8984/9/38/014

Cited by 13 publications

(18 citation statements)

References 47 publications

(129 reference statements)

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“…In 3D the relevant comparison is with the vortex glass 24 which has been argued extensively to be a superconducting phase. We find instead that this state is metallic 25,26,27 .…”

Section: Introductioncontrasting

confidence: 53%

“…Because of the equivalence of the phase glass to a vortex glass in the presence of magnetic field, our results imply that the linear conductivity should remain finite in the vortex glass. These results are discussed extensively in the context of the insulator-superconductor transition and the recent experiments that indicate that the vortex glass state is not accompanied 26,27 by a vanishing of the linear I-V characteristics.…”

Section: Magnetic Field: Summary Of Findingsmentioning

confidence: 88%

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Vortex glass is a metal: Unified theory of the magnetic-field and disorder-tuned Bose metals

Phillips

2006

Phys. Rev. B

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We consider the disordered quantum rotor model in the presence of a magnetic field. We analyze the transport properties in the vicinity of the multicritical point between the superconductor, phase glass and paramagnetic phases. We find that the magnetic field leaves metallic transport of bosons in the glassy phase in tact. In the vicinity of the vicinity of the superconductivity-to-Bose metal transition, the resistitivy turns on as (H − Hc) 2 with Hc. This functional form is in excellent agreement with the experimentally observed turn-on of the resistivity in the metallic state in MoGe, namely R ≈ Rc(H − Hc) µ , 1 < µ < 3. The metallic state is also shown to presist in three spatial dimensions. In addition, we also show that the metallic state remains intact in the presence of Ohmic dissipation in spite of recent claims to the contrary. As the phase glass in d = 3 is identical to the vortex glass, we conclude that the vortex glass is, in actuality, a metal rather than a superconductor at T = 0. Our analysis unifies the recent experiments on vortex glass systems in which the linear resistivity remained non-zero below the putative vortex glass transition and the experiments on thin films in which a metallic phase has been observed to disrupt the direct transition from a superconductor to an insulator.

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“…In 3D the relevant comparison is with the vortex glass 24 which has been argued extensively to be a superconducting phase. We find instead that this state is metallic 25,26,27 .…”

Section: Introductioncontrasting

confidence: 53%

Section: Magnetic Field: Summary Of Findingsmentioning

confidence: 88%

Vortex glass is a metal: Unified theory of the magnetic-field and disorder-tuned Bose metals

Phillips

2006

Phys. Rev. B

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“…Correspondingly no scaling behaviour of the E − J curves were found [24,25]. This suggests that in previous works the twin boundaries might have played the role of extended defects, and in fact the observed scaling behaviour was that of the Bose Glass.…”

mentioning

confidence: 91%

Vortices Freeze like Window Glass: The Vortex Molasses Scenario

Reichhardt

A²,

2000

Phys. Rev. Lett.

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We overview several recent experimental and numerical observations, which are at odds with the Vortex Glass theory of the freezing of disordered vortex matter. To reinvestigate the issue, we performed numerical simulations of the overdamped London -Langevin model, and use finite size scaling to analyze the data. Upon approaching the transition the initial Vortex Glass type criticality is arrested at some crossover temperature. Below this temperature the timescales continue growing very quickly, consistent with the Vogel-Fulcher form, while the spatial correlation length ξ stops exhibiting any observable divergence. We call this mode of freezing the Vortex Molasses scenario.PACS numbers: 74.60.Ge, 74.25.DwThe influence of disorder on vortex matter is one of the most paradigmatic problems. The vortex lattice, formed in clean systems, is inherently unstable towards a less ordered state even for infinitesimally small disorder [1]. At small magnetic fields, or equivalently, at weak disorder, a dislocation free phase is emerges, which thus retains a topological order. Small angle neutron scattering [2], and Bitter decoration experiments [3] seem to support this picture. The theoretical foundation for such a Bragg Glass was provided by scaling arguments [4], and variational calculations [5]. Its cornerstone is the logarithmic behaviour of vortex correlations at large distances. Numerical simulations also reported a strongly suppressed dislocation density [6], and confirmed the logarithmic behaviour of correlations [7] below a critical field strength. It is noteworthy, however, that the largest scale imaging studies [8], did not find evidence for logarithmic correlations, thus the details of the dislocation free regime are still subject to discussion.We also understand the influence of increasing fields, or disorder. The key phenomenon here is the appearance of dislocation loops, accompanied by the entanglement of vortices [9,10]. Experimental support for this idea is the sharp enhancement of the critical current from magnetization measurements [11][12][13][14], the rapid destruction of the Bragg peaks in neutron scattering [2], and the pronounced dips in the electric field -current density, or E-J curves [15]. Numerical studies found evidence for dislocation loops destroying a quasi-ordered state in frustrated XY models [16], in Lawrence-Doniach representations [6], and in realistic London-Langevin approaches [7].The nature of the high field phase is still very much in debate. The thermally assisted flux flow (TAFF) picture predicts that vortices move in bundles, and overcome barriers via thermal excitations. This destroys superconductivity because the linear resistivity assumes a finite value, governed by an activated temperature dependence R(T ) ∼ R 0 exp(−U/T ) [17]. An influential alternative was put forward in the form of the Vortex Glass (VG) theory [18,19]. The proposed Vortex Glass phase is distinguished by an unbounded distribution of barrier heights. This results in the vanishing of the linear resistivity, th...

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“…Originally, the proposition that the IRL signals the continuous VG-VL phase transition was supported by experiments showing the scaling of the current-voltage characteristic, 28,29 and by simulations in randomly frustrated 3D XY models without screening showing evidence for a finite temperature critical point. 14,20,30 However, contradictions in the experimental scaling of the currentvoltage characteristics, 29,31,32 on the one hand, and the disappearance of the finite temperature transition in the randomly frustrated 3D XY model when screening is restored, 15,16,17,18 on the other hand, have raised new questions on how to interpret the IRL.…”

Section: Introductionmentioning

confidence: 99%

Langevin simulations of the out-of-equilibrium dynamics of vortex glasses in high-temperature superconductors

2007

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We study the relaxation dynamics of flux lines in dirty high-temperature superconductors using numerical simulations of a London-Langevin model of the interacting vortex lines. By analysing the equilibrium dynamics in the vortex liquid phase we find a dynamic crossover to a glassy non-equilibrium regime. We then focus on the out-of-equilibrium dynamics of the vortex glass phase using tools that are common in the study of other glassy systems. By monitoring the two-times roughness and dynamic wandering we identify and characterize finite-size effects that are similar, though more complex, than the ones found in the stationary roughness of clean interface dynamics. The two-times density-density correlation and mean-squared-displacement correlation age and their temporal scaling follows a multiplicative law similar to the one found at criticality. The linear responses also age and the comparison with their associated correlations shows that the equilibrium fluctuationdissipation relation is modified in a simple manner that allows for the identification of an effective temperature characterizing the dynamics of the slow modes. The effective temperature is closely related to the vortex liquidvortex glass crossover temperature. Interestingly enough, our study demonstrates that the glassy dynamics in the vortex glass is basically identical to the one of a single elastic line in a disordered environment (with the same type of scaling though with different parameters). Possible extensions and the experimental relevance of these results are also discussed.

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Current-driven vortex dynamics in untwinned superconducting single crystals

Cited by 13 publications

References 47 publications

Vortex glass is a metal: Unified theory of the magnetic-field and disorder-tuned Bose metals

Vortex glass is a metal: Unified theory of the magnetic-field and disorder-tuned Bose metals

Vortices Freeze like Window Glass: The Vortex Molasses Scenario

Langevin simulations of the out-of-equilibrium dynamics of vortex glasses in high-temperature superconductors

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