Tunneling Between High-T_c Oxide and Normal Metal

In slave-fermion representation t - J model is adopted to study the tunneling between high-T_c oxide and normal metal. The differential conductance shows an asymmetric V-shape behavior on a constant background. The constant results from the motions of holons on the background of the spiral antiferromagnetism produced by partially condensed spinons. The asymmetry changes with hole concentration and becomes insignificant in the region optimal for high-T_c superconductivity.