Theory of giant and nil proximity effects in cuprate semiconductors

TL;DR

This paper presents an analytical solution to the Gross-Pitaevskii equation that explains the experimentally observed nil and giant proximity effects in cuprate superconductors, suggesting they may originate from Bose-Einstein condensation of bipolarons.

Contribution

It introduces a theoretical model based on Bose-Einstein condensation to explain proximity effects in cuprates, challenging conventional BCS theory.

Findings

Qualitative and quantitative agreement with experimental proximity effects

Supports bipolaron BEC as the origin of high-Tc superconductivity

Provides analytical solutions for bose-condensate tunnelling

Abstract

A number of observations point to the possibility that high-Tc cuprate superconductors may not be conventional Bardeen-Cooper-Schrieffer (BCS) superconductors, but rather derive from the Bose-Einstein condensation (BEC) of real-space pairs, which are mobile small bipolarons. A solution of the Gross-Pitaevskii equation describing bose-condensate tunnelling into a cuprate semiconductor is analytically found. It accounts qualitatively and quantitatively for nil and giant proximity effects discovered experimentally in cuprates.