Theory of High-Tc Superconductivity: Accurate Predictions of Tc

TL;DR

This paper presents a universal theoretical framework for predicting high-temperature superconducting transition temperatures based on structural and electronic parameters, achieving close agreement with experimental data.

Contribution

It introduces a universal formula for T_c0 depending on bond lengths, ionic valences, and Coulomb interactions, providing accurate predictions for various high-Tc compounds.

Findings

Predicted T_c0 values agree with experimental data within +/- 1.4 K for tested compounds.

Universal expression involves Coulomb forces and geometric parameters of layered structures.

The theory suggests Compton scattering may influence electron pairing in high-Tc superconductors.

Abstract

The superconducting transition temperatures of high-Tc compounds based on copper, iron, ruthenium and certain organic molecules are discovered to be dependent on bond lengths, ionic valences, and Coulomb coupling between electronic bands in adjacent, spatially separated layers [1]. Optimal transition temperature, denoted as T_c0, is given by the universal expression $k_BT_c0 = e^2 \Lambda / \ell\zeta$; $\ell$ is the spacing between interacting charges within the layers, \zeta is the distance between interacting layers and \Lambda is a universal constant, equal to about twice the reduced electron Compton wavelength (suggesting that Compton scattering plays a role in pairing). Non-optimum compounds in which sample degradation is evident typically exhibit Tc < T_c0. For the 31+ optimum compounds tested, the theoretical and experimental T_c0 agree statistically to within +/- 1.4 K. The elemental high Tc building block comprises two adjacent and spatially separated charge layers; the factor e^2/\zeta arises from Coulomb forces between them. The theoretical charge structure representing a room-temperature superconductor is also presented.