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Screening effects in superconductors

Massimiliano Capezzali·Daniel Ariosa·Hans Beck
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Abstract

The partition function of the Hubbard model with local attraction and long range Coulomb repulsion between electrons is written as a functional integral with an action $A$ involving a pairing field $Δ$ and a local potential $V$. After integration over $V$ and over fluctuations in $|Δ|^{2}$, the final form of $A$ involves a Josephson coupling between the local phases of $Δ$ and a "kinetic energy" term, representing the screened Coulomb interaction between charge fluctuations. The competition between Josephson coupling and charging energy allows to understand the relation between $T_{C}$ and composition in high-$T_{C}$ materials, in particular superlattices, alloys and bulk systems of low doping.

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Massimiliano Capezzali, Daniel Ariosa, Hans Beck. 1996-08-26. Screening effects in superconductors. https://doi.org/10.1016/s0921-4526(96)00712-0

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