Non-equilibrium superconductivity in homogeneous thin films

Pals, J.A.; Weiss, Katja; Attekum, P. M. Th. M. van; Horstman, RT; Wolter, J.H.

doi:10.1016/0370-1573(82)90071-0

Cited by 42 publications

(21 citation statements)

References 118 publications

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“…25 Indeed, a change of the superconducting gap after a laser pulse excitation has been demonstrated experimentally. 26,27 Ultrafast dynamics of electrons in high-T c copper oxides was also investigated with several different methods.…”

Section: ' Results and Discussionmentioning

confidence: 99%

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)₂I₃ Using a Nanosecond Laser Pulse

et al. 2011

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Time-resolved photoresponses in resistance have been measured following the nanosecond laser pulse excitation for the quasi-two-dimensional organic superconductors of hydrogenated and deuterated β-(BEDT-TTF)2I3 [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene], which show two different superconducting states with high-T c and low-T c, at temperatures near the critical temperatures. A transient increase of the resistance is induced by photoirradiation at all the temperatures, but a marked temperature dependence of the decay time is observed at temperatures close to the high-T c phase transition temperature; the decay rate becomes faster and then becomes constant in both compounds, as the temperature decreases across the high-T c phase transition temperature. The temperature dependence of the photoresponse intensity is different from the one expected from the bolometric effects, indicating the presence of the nonbolometric photoresponse. A possible mechanism explaining the photoresponse of the conductivity is discussed, based on the isotope effect on the photoresponse. A comparison is also made between β-(BEDT-TTF)2I3 and κ-(BEDT-TTF)2Cu[N(CN)2]Br for the transient photoresponse in resistance at temperatures across the metal-superconductor phase transition temperature.

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Section: ' Results and Discussionmentioning

confidence: 99%

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)₂I₃ Using a Nanosecond Laser Pulse

et al. 2011

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“…In general, photons of energy greater than the Cooper pair binding energy (2∆) can initiate a chain of pair-breaking events resulting in a deviation of the quasiparticle and pair densities from their equilibrium values. Typically, these distributions depend on temperature, optical power and wavelength, thermal boundary conditions, and material properties such as electron-electron and electron-phonon interactions times, electron density, coherence length, penetration depth, and geometry 6,14 . While determining the spatial and temporal distribution of quasiparticles and pairs under a time-varying optical illumination is a profound problem in non-equilibrium superconductivity, many of the important concepts of such an interaction for device applications can be captured by means of a much simpler and more phenomenological approach, namely the kinetic inductance model 13 .…”

mentioning

confidence: 99%

Ultrafast linear kinetic inductive photoresponse of YBa2Cu3O7−δ meander-line structures by photoimpedance measurements

Atikian

Ghamsari

Anlage

et al. 2011

Applied Physics Letters

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We report the experimental demonstration of the linear kinetic-inductive photoresponse of thin-film YBa 2 Cu 3 O 7−δ (YBCO) meander-line structures, where the photoresponse amplitude, full-width-halfmaximum (FWHM), and rise-time are bilinear in the incident optical power and bias current. This bilinear behavior reveals a trade-off between obtaining high responsivity and high speed photodetection. We also report a rise-time as short as 29ps in our photoimpedance measurements.The interaction of light with superconducting samples is long known to perturb superconductivity 1-4 , which can be used as a probing mechanism for optoelectronic applications 5-13 . In general, photons of energy greater than the Cooper pair binding energy (2∆) can initiate a chain of pair-breaking events resulting in a deviation of the quasiparticle and pair densities from their equilibrium values. Typically, these distributions depend on temperature, optical power and wavelength, thermal boundary conditions, and material properties such as electron-electron and electron-phonon interactions times, electron density, coherence length, penetration depth, and geometry 6,14 . While determining the spatial and temporal distribution of quasiparticles and pairs under a time-varying optical illumination is a profound problem in non-equilibrium superconductivity, many of the important concepts of such an interaction for device applications can be captured by means of a much simpler and more phenomenological approach, namely the kinetic inductance model 13 . Within the kinetic inductance model the presence of the superconductive condensate, at a macroscopic level, can be adequately modeled by an additional inductive channel for charge transport. The optically initiated pair breaking mechanism, within this framework, should be interpreted as the spatial and temporal variations of the kinetic inductance and the normal resistance of the superconducting specimen.Many researchers have experimentally studied the kinetic inductive photoresponse of superconducting thin films through photoimpedance measurements 6,15 . In photoimpedance measurements, light induced changes in the microwave impedance of the superconducting structure are measured by an external high-frequency circuit. In its simplest form, the specimen is externally biased with a dc current and connected to a fast oscilloscope in series with a high bandwidth amplifier; absorption of optical photons then changes the impedance of the sample and produces a transient voltage response. A number a) Author to whom correspondence should be addressed. Electronic address: haatikia@maxwell.uwaterloo.ca of previous works have reported photoimpedance measurements on different superconductors mainly concluding that: 1) the resistive photoresponse dominates at temperatures well below the critical temperature (T c ), whereas the kinetic inductive response becomes the main mechanism of photoresponse close to T c ; 2) In the kinetic inductive regime the photoresponse could be very fast, with a rise time as low as 50...

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“…This equation has been used above as an initial one to obtain (10) and (11) and it describes only the dynamic processes of nondissipative character. In the phenomenological theory of nonstationary superconductivity, the dissipation effects are usually attained by using the time-dependent Ginzburg-Landau (TDGL) equation [18][19][20][21]. The TDGL equation is a generalization of the ordinary GL equation (originally obtained [16] for the steady-state nonuniform superconductors) to time-varying situations.…”

Section: Madelung-feynman's Approach To the Quantum-mechan-mentioning

confidence: 99%

“…As applied to the superfluid dynamics in superconductors, the problem of quantum dissipation is treated in the form of the time-dependent Ginzburg-Landau (TDGL) equation (e.g., see [15]). Generalization of the usual Ginzburg-Landau (GL) stationary theory [16][17][18] to timevarying situations was the subject of much investigation (e.g., see reviews [19][20][21]). However, all known versions of the TDGL equation suffer from a general drawback: they have no charge conservation property, that is, do not provide the continuity equation for the superfluid flow (but not for the total flow, superfluid and normal fluid together) (see the text after formula (38)).…”

Section: Introductionmentioning

confidence: 99%

Nonstationary Superconductivity: Quantum Dissipation and Time-Dependent Ginzburg-Landau Equation

Barybin¹

2011

Advances in Condensed Matter Physics

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Transport equations of the macroscopic superfluid dynamics are revised on the basis of a combination of the conventional (stationary) Ginzburg-Landau equation and Schrödinger's equation for the macroscopic wave function (often called the order parameter) by using the well-known Madelung-Feynman approach to representation of the quantum-mechanical equations in hydrodynamic form. Such an approach has given (a) three different contributions to the resulting chemical potential μ s for the superfluid component, (b) a general hydrodynamic equation of superfluid motion, (c) the continuity equation for superfluid flow with a relaxation term involving the phenomenological parameters τ GL and ξ GL , (d) a new version of the time-dependent Ginzburg-Landau equation for the modulus of the order parameter which takes into account dissipation effects and reflects the charge conservation property for the superfluid component. The conventional Ginzburg-Landau equation also follows from our continuity equation as a particular case of stationarity. All the results obtained are mutually consistent within the scope of the chosen phenomenological description and, being model-neutral, applicable to both the low-T c and high-T c superconductors.

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Non-equilibrium superconductivity in homogeneous thin films

Cited by 42 publications

References 118 publications

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)₂I₃ Using a Nanosecond Laser Pulse

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)₂I₃ Using a Nanosecond Laser Pulse

Ultrafast linear kinetic inductive photoresponse of YBa2Cu3O7−δ meander-line structures by photoimpedance measurements

Nonstationary Superconductivity: Quantum Dissipation and Time-Dependent Ginzburg-Landau Equation

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Non-equilibrium superconductivity in homogeneous thin films

Cited by 42 publications

References 118 publications

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)2I3 Using a Nanosecond Laser Pulse

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)2I3 Using a Nanosecond Laser Pulse

Ultrafast linear kinetic inductive photoresponse of YBa2Cu3O7−δ meander-line structures by photoimpedance measurements

Nonstationary Superconductivity: Quantum Dissipation and Time-Dependent Ginzburg-Landau Equation

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Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)₂I₃ Using a Nanosecond Laser Pulse

Time-Resolved Photoresponse Measurements of the Electrical Conductivity of the Quasi-Two-Dimensional Organic Superconductor β-(BEDT-TTF)₂I₃ Using a Nanosecond Laser Pulse