Did Herbert Fröhlich predict or postdict the isotope effect in superconductors?

Hirsch, J. E.

doi:10.1088/0031-8949/84/04/045705

Cited by 4 publications

(2 citation statements)

References 39 publications

(69 reference statements)

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“…[1][2][3] The theory arose at about the same time as experimental confirmation by Maxwell 4 and Reynolds et al 5,6 using Hg. This effect gained further relevance after subsequent incorporation of EPI in the BCS theory of superconductivity.…”

Section: Introductionmentioning

confidence: 78%

“…The electron-phonon interaction (EPI) and its verification through the isotope effect (IE) have played important roles in the validation of superconductivity since Fro ¨hlich suggested the idea and a theory in 1950. [1][2][3] The theory arose at about the same time as experimental confirmation by Maxwell 4 and Reynolds et al 5,6 using Hg. This effect gained further relevance after subsequent incorporation of EPI in the BCS theory of superconductivity.…”

Section: Introductionmentioning

confidence: 99%

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Coherent phonon decay and the boron isotope effect for MgB₂

Alarco

Talbot

2014

Phys. Chem. Chem. Phys.

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Ab initio DFT calculations for the phonon dispersion (PD) and the phonon density of states (PDOS) of the two isotopic forms ((10)B and (11)B) of MgB2 demonstrate that use of a reduced symmetry super-lattice provides an improved approximation to the dynamical, phonon-distorted P6/mmm crystal structure. Construction of phonon frequency plots using calculated values for these isotopic forms gives linear trends with integer multiples of a base frequency that change in slope in a manner consistent with the isotope effect (IE). Spectral parameters inferred from this method are similar to that determined experimentally for the pure isotopic forms of MgB2. Comparison with AlB2 demonstrates that a coherent phonon decay down to acoustic modes is not possible for this metal. Coherent acoustic phonon decay may be an important contributor to superconductivity for MgB2.

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Section: Introductionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Coherent phonon decay and the boron isotope effect for MgB₂

Alarco

Talbot

2014

Phys. Chem. Chem. Phys.

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Correcting 100 Years of Misunderstanding: Electric Fields in Superconductors, Hole Superconductivity, and the Meissner Effect

Hirsch

2012

J Supercond Nov Magn

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From the outset of superconductivity research it was assumed that no electrostatic fields could exist inside superconductors, and this assumption was incorporated into conventional London electrodynamics. Yet the London brothers themselves initially (in 1935) had proposed an electrodynamic theory of superconductors that allowed for static electric fields in their interior, which they unfortunately discarded a year later. I argue that the Meissner effect in superconductors necessitates the existence of an electrostatic field in their interior, originating in the expulsion of negative charge from the interior to the surface when a metal becomes superconducting. The theory of hole superconductivity predicts this physics, and associated with it a macroscopic spin current in the ground state of superconductors ("Spin Meissner effect"), qualitatively different from what is predicted by conventional BCS-London theory. A new London-like electrodynamic description of superconductors is proposed to describe this physics. Within this theory superconductivity is driven by lowering of quantum kinetic energy, the fact that the Coulomb repulsion strongly depends on the character of the charge carriers, namely whether electron-or hole-like, and the spin-orbit interaction. The electron-phonon interaction does not play a significant role, yet the existence of an isotope effect in many superconductors is easily understood. In the strong coupling regime the theory appears to favor local charge inhomogeneity. The theory is proposed to apply to all superconducting materials, from the elements to the high Tc cuprates and pnictides, is highly falsifiable, and explains a wide variety of experimental observations.

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Superconductivity in the elements, alloys and simple compounds

Webb

Marsiglio

Hirsch

2015

Physica C: Superconductivity and its Applications

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We give a brief review of superconductivity at ambient pressure in elements, alloys, and simple three-dimensional compounds. Historically these were the first superconducting materials studied, and based on the experimental knowledge gained from them the BCS theory of superconductivity was developed in 1957. Extended to include the effect of phonon retardation, the theory is believed to describe the subset of superconducting materials known as `conventional superconductors', where superconductivity is caused by the electron-phonon interaction. These include the elements, alloys and simple compounds discussed in this article and several other classes of materials discussed in other articles in this Special Issue.Comment: Accepted for publication in Physica C, Special Issue on Superconducting Material

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Did Herbert Fröhlich predict or postdict the isotope effect in superconductors?

Cited by 4 publications

References 39 publications

Coherent phonon decay and the boron isotope effect for MgB₂

Coherent phonon decay and the boron isotope effect for MgB₂

Correcting 100 Years of Misunderstanding: Electric Fields in Superconductors, Hole Superconductivity, and the Meissner Effect

Superconductivity in the elements, alloys and simple compounds

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Did Herbert Fröhlich predict or postdict the isotope effect in superconductors?

Cited by 4 publications

References 39 publications

Coherent phonon decay and the boron isotope effect for MgB2

Coherent phonon decay and the boron isotope effect for MgB2

Correcting 100 Years of Misunderstanding: Electric Fields in Superconductors, Hole Superconductivity, and the Meissner Effect

Superconductivity in the elements, alloys and simple compounds

Contact Info

Product

Resources

About

Coherent phonon decay and the boron isotope effect for MgB₂

Coherent phonon decay and the boron isotope effect for MgB₂