摘要
In this letter,we propose a modified attractive Hubbard model at half filling that can exhibit sup er con ductivity through η-pairing mecha.nism in spin-density wave representation and derive a concise relationship between the energy disparity and the single-particle energy spectrum.This relationship,in the two limits of U,clearly shows that the system does not display sup er con ductivity for very low doping concen・tration.but denionst.ra.tes s up ere on ductivity when the doping concentration exceeds a certain critical value.This conclusion is in quaJitative agreement with the familiar experiments on higli-T_(c) supcrconductivity.
