MECHANISM OF PARAMAGNETIC MEISSNER EFFECT IN HIGH-TEMPERATURE SUPERCONDUCTORS

A possible mechanism of paramagnetic Meissner effect observed in some high-temperature superconductors is proposed. It is shown that a param agnetic Meissner current flows if there exists a large quasi-particle density of states around zero energy in the energy gap. This suggests that the paramagnetic Meissner effect is associated with a zero-bias c onductance peak which has often been observed in the tunnelling experi ments of high-temperature superconductors. The paramagnetic effect cau sed by the zero-energy, excitations is consistent with the experiments .