T-Jperp model and a possible pairing mechanism in the oxide superconductors.

Abstract

We introduce the ``t-${\mathit{J}}_{\mathrm{\ensuremath{\perp}}}$'' model as the presence of holes in a two-dimensional XY spin-1/2 antiferromagnet, which gives rise to charged particles that carry flux. We find that the problem can be mapped into electrodynamics with constraints, leading to scalar and transversal vector potentials generated by the vorticity charges Q(x)=m(x)+(1/2\ensuremath{\pi}\ensuremath{\theta})\ensuremath{\rho}(x) and their currents. Here m(x)=0,\ifmmode\pm\else\textpm\fi{}1 are chargeless vortices, and \ensuremath{\rho}(x) is the density of the electric charges. The scalar potential between the electric charges \ensuremath{\rho}(x) is generated by the neutral vortices m(x). The direct repulsive interaction between the electric charges is screened out by the neutral vortex excitations giving rise to attraction at large distance. The currents produced by the vortices give rise to gauge fields that also include a Chern-Simons term. The gauge fields represent the transversal part of electrodynamics in 2+1 dimensions and might be responsible for normal-state properties such as linear resistivity.