Calculation of Tc of Superconducting Elements with the Roeser–Huber Formalism

Koblischka, Michael Rudolf; Koblischka-Veneva, Anjela

doi:10.3390/met12020337

Cited by 10 publications

(8 citation statements)

References 33 publications

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“…We also showed how the proposed classification scheme is linked to other known empirical scaling laws and taxonomies in superconductivity [ 13 , 17 , 18 , 19 , 20 , 21 ]; meanwhile, the search for the link of the proposed taxonomy with the recently reported big data [ 22 , 23 ] is under progress.…”

Section: Introductionmentioning

confidence: 99%

Quantifying Nonadiabaticity in Major Families of Superconductors

Talantsev

2022

Nanomaterials

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The classical Bardeen–Cooper–Schrieffer and Eliashberg theories of the electron–phonon-mediated superconductivity are based on the Migdal theorem, which is an assumption that the energy of charge carriers, kBTF, significantly exceeds the phononic energy, ℏωD, of the crystalline lattice. This assumption, which is also known as adiabatic approximation, implies that the superconductor exhibits fast charge carriers and slow phonons. This picture is valid for pure metals and metallic alloys because these superconductors exhibit ℏωDkBTF<0.01. However, for n-type-doped semiconducting SrTiO3, this adiabatic approximation is not valid, because this material exhibits ℏωDkBTF≅50. There is a growing number of newly discovered superconductors which are also beyond the adiabatic approximation. Here, leaving aside pure theoretical aspects of nonadiabatic superconductors, we classified major classes of superconductors (including, elements, A-15 and Heusler alloys, Laves phases, intermetallics, noncentrosymmetric compounds, cuprates, pnictides, highly-compressed hydrides, and two-dimensional superconductors) by the strength of nonadiabaticity (which we defined by the ratio of the Debye temperature to the Fermi temperature, TθTF). We found that the majority of analyzed superconductors fall into the 0.025≤TθTF≤0.4 band. Based on the analysis, we proposed the classification scheme for the strength of nonadiabatic effects in superconductors and discussed how this classification is linked with other known empirical taxonomies in superconductivity.

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Section: Introductionmentioning

confidence: 99%

Quantifying Nonadiabaticity in Major Families of Superconductors

Talantsev

2022

Nanomaterials

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“…These practical applications are: superconducting cables [71][72][73], superconducting fault current limiters [74,75], and superconducting transformers [76][77][78][79]. The scaling laws proposed in this work extend the established family of scaling laws [4,5,[80][81][82][83][84] in superconductivity.…”

Section: Discussionmentioning

confidence: 69%

New Scaling Laws for Pinning Force Density in Superconductors

Talantsev

2022

Condensed Matter

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Since the report by Fietz and Webb (Phys. Rev.1968, 178, 657–667), who considered the pinning force density, Fp→=Jc→×B→ (where Jc is the critical current density and B is applied magnetic flux density), in isotropic superconductors as a unique function of reduced magnetic field, BBc2 (where Bc2 is the upper critical field), Fp→ has been scaled based on the BBc2 ratio, for which there is a widely used Kramer–Dew–Hughes scaling law of Fp→B=Fp,maxBBc2p1−BBc2q, where Fp,max, Bc2, p, and q are free-fitting parameters. To describe Fp→B in high-temperature superconductors, the Kramer–Dew–Hughes scaling law has been modified by (a) an assumption of the angular dependence of all parameters and (b) by the replacement of the upper critical field, Bc2, by the irreversibility field, Birr. Here, we note that Fp→ is also a function of critical current density, and thus, the Fp→Jc scaling law should exist. In an attempt to reveal this law, we considered the full Fp→B,Jc function and reported that there are three distinctive characteristic ranges of BBc2,JcJcsf (where Jcsf is the self-field critical current density) on which Fp→B,Jc can be splatted. Several new scaling laws for Fp→Jc were proposed and applied to MgB2, NdFeAs(O,F), REBCO, (La,Y)H10, and YH6. The proposed scaling laws describe the in-field performance of superconductors at low and moderate magnetic fields, and thus, the primary niche for these laws is superconducting wires and tapes for cables, fault current limiters, and transformers.

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“…For kBT ≪ εF, we ignore the temperature dependency of the chemical potential, m, in the Fermi-Dirac function and replace m by the constant ε F . Let kBT � τ, and consider the Fermi-Dirac distribution function [25,26].…”

Section: Electronic Heat Capacitymentioning

confidence: 99%

Thermal and Electronic Conductivity in Normal and Superconducting Erbium Nickel Borocarbide (ErNi2B2C)

Tesfaye

2022

Advances in Materials Science and Engineering

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In this work, the total electronic energy, the electronic thermal conductivity, and the heat capacity of erbium nickel borocarbide, ErNi2B2C, in the normal and superconducting states are calculated using Boltzmann transport equations (BTEs) and energy dispersion relation function. Results from the electronic thermal conductivity versus temperature (T) are presented. From the result, electrical and thermal conductivity at low temperature obey the Wiedemann–Franz law. Moreover, at the normal state, the electronic thermal conductivity of ErNi2B2C is directly proportional to the temperature (T) and reaches its maximum (kink) at the transition temperature, Tc. After the superconducting transition temperature, the electronic thermal conductivity begin to decrease. The drop in electronic thermal conductivity beyond its peak (kink) value is due to the formation of energy gap and the absence of Cooper pairs.

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Calculation of Tc of Superconducting Elements with the Roeser–Huber Formalism

Cited by 10 publications

References 33 publications

Quantifying Nonadiabaticity in Major Families of Superconductors

Quantifying Nonadiabaticity in Major Families of Superconductors

New Scaling Laws for Pinning Force Density in Superconductors

Thermal and Electronic Conductivity in Normal and Superconducting Erbium Nickel Borocarbide (ErNi2B2C)

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