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 ${\ensuremath{\Delta}}_{\mathrm{SDW}}$ 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 ${V}_{k\mathrm{\ensuremath{-}}k\mathcal{'}}$ leads to a superconducting energy gap ${\ensuremath{\Delta}}_{\mathrm{SC}}$ which is nodeless over the Fermi surface, where ${\ensuremath{\Delta}}_{\mathrm{SC}\mathrm{\ensuremath{\simeq}}{\ensuremath{\Delta}}_{\mathrm{SDW}\mathrm{exp}(\mathrm{\ensuremath{-}}\mathit{t}/\mathit{\ensuremath{\alpha}}\mathit{U}}}$), with \ensuremath{\alpha} of order unity.