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Berdiyorov G.,Loughborough University | Berdiyorov G.,Qatar Environment and Energy Research Institute | Harrabi K.,King Fahd University of Petroleum and Minerals | Maneval J.P.,Laboratoire Pierre Aigrain | Peeters F.M.,University of Antwerp
Superconductor Science and Technology | Year: 2015

Using the anisotropic time-dependent Ginzburg-Landau theory we study the effect of ordered and disordered pinning on the time response of superconducting strips to an external current that switched on abruptly. The pinning centers result in a considerable delay of the response time of the system to such abrupt switching on of the current, whereas the output voltage is always larger when pinning is present. The resistive state in both cases are characterized either by dynamically stable phase-slip centers/lines or expanding in-time hot-spots, which are the main mechanisms for dissipation in current-carrying superconductors. We find that hot-spots are always initiated by the phase-slip state. However, the range of the applied current for the phase-slip state increases significantly when pinning is introduced. Qualitative changes are observed in the dynamics of the superconducting condensate in the presence of pinning. © 2015 IOP Publishing Ltd. Source


Estienne B.,University Pierre and Marie Curie | Regnault N.,Laboratoire Pierre Aigrain | Santachiara R.,University Paris - Sud
Nuclear Physics B | Year: 2010

Recently, Jack polynomials have been proposed as natural generalizations of Zk Read-Rezayi states describing non-Abelian fractional quantum Hall systems. These polynomials are conjectured to be related to correlation functions of a class of W-conformal field theories based on the Lie algebra Ak - 1. These theories can be considered as non-unitary solutions of a more general series of CFTs with Zk symmetry, the parafermionic theories. Starting from the observation that some parafermionic theories admit unitary solutions as well, we show, by computing the corresponding correlation functions, that these theories provide trial wavefunctions which satisfy the same clustering properties as the non-unitary ones. We show explicitly that, although the wavefunctions constructed by unitary CFTs cannot be expressed as a single Jack polynomial, they still show a fine structure where the mathematical properties of the Jack polynomials play a major role. © 2009 Elsevier B.V. All rights reserved. Source


Harrabi K.,King Fahd University of Petroleum and Minerals | Harrabi K.,Laboratoire Pierre Aigrain
Journal of Superconductivity and Novel Magnetism | Year: 2013

In a superconducting microbridge too narrow to support vortex motion, the current-induced resistance occurs non-uniformly at definite spots designated as Phase-Slip-Centres (PSC). Further, if the core of a PSC happens to heat above the critical temperature Tc, a PSC may evolve into a normal propagating zone, or hotspot. The PSC's time of nucleation and the HS minimum current Ih are determined, which allows deriving without ambiguity the rate of heat transfer to the substrate, the latter is compatible with a phonon blackbody radiation model at the Nb/R-sapphire interface. The computation of the HS temperature is then straightforward, while the PSC case is more involved. However, the PSC core temperature can be obtained through an independent determination of the inelastic quasi-particle diffusion length Λqp∼2.8 μm. The results of these computations are consistent with all the specific cases, PSCs and HSs, measured experimentally. © 2013 Springer Science+Business Media New York. Source


Berdiyorov G.,Loughborough University | Berdiyorov G.,King Fahd University of Petroleum and Minerals | Harrabi K.,King Fahd University of Petroleum and Minerals | Oktasendra F.,King Fahd University of Petroleum and Minerals | And 4 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

Phase-slip centers/lines and hot spots are the main mechanisms for dissipation in current-carrying superconducting thin films. The pulsed-current method has recently been shown to be an effective tool in studying the dynamics of phase-slip centers and their evolution to hot spots. We use the time-dependent Ginzburg-Landau theory in the study of the dynamics of the superconducting condensate in superconducting strips under external current and zero external magnetic field. We show that both the flux-flow state (i.e., slow-moving vortices) and the phase-slip line state (i.e., fast-moving vortices) are dynamically stable dissipative units with temperature smaller than the critical one, whereas hot spots, which are localized normal regions where the local temperature exceeds the critical value, expand in time, resulting ultimately in a complete destruction of the condensate. The response time of the system to abrupt switching on of the overcritical current decreases with increasing both the value of the current (at all temperatures) and temperature (for a given value of the applied current). Our results are in good qualitative agreement with experiments we have conducted on Nb thin strips. © 2014 American Physical Society. Source


Bowlan P.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie | Kuehn W.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie | Reimann K.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie | Woerner M.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie | And 3 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Charge transport in an electron-hole plasma driven by high-field terahertz (THz) pulses is strongly influenced by electron-hole interactions, as has been shown in a recent publication. We introduce a picture of high-field THz transport which accounts for the roles of both types of carriers including their interactions. While holes make a negligible contribution to the current, they are heated by absorbing energy from the driving THz field and introduce a friction force for the electrons over a period of about 500 fs. Our model uses an extended version of the loss-function concept to calculate the time-dependent friction. The local field that drives the electrons differs from the incident THz field by screening due to Coulomb correlations in the plasma. We illustrate how spatial correlations between charged particles (electrons, holes, impurities) create a significant local-field correction to the THz driving field. The dominant contribution stems from Coulomb-correlated heavy-hole wave packets, which are strongly polarizable via inter-valence-band transitions. © 2012 American Physical Society. Source

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