Spin-bag mechanism of high-temperature superconductivity

Abstract

A new approach to the theory of high-temperature superconductivity is proposed, based on the two-dimensional antiferromagnetic spin correlations observed in these materials over distances large compared to the lattice spacing. The spin ordering produces an electronic pseudogap ${\Delta }_{\mathrm{SDW}}$ which is locally suppressed by the addition of a hole. This suppression forms a bag inside which the hole is self-consistently trapped. Two holes are attracted by sharing a common bag. The resulting pairing interaction $V_{k\mathrm{-}k\mathcal{’}}$ leads to a superconducting energy gap ${\Delta }_{\mathrm{SC}}$ which is nodeless over the Fermi surface, where ${\Delta }_{\mathrm{SC}\mathrm{\simeq }{\Delta }_{\mathrm{SDW}\exp (\mathrm{-}\mathit{t}/\mathit{\alpha }\mathit{U}}}$), with α of order unity.