Effect of Bi 2 Sr 2 CaCu 2 O y Single Crystal Surfaces on Contact Resistance

We formed Au electrodes on the surfaces of Bi 2 Sr 2 CaCu 2 O y single crystals and investigated the effect of the surfaces on the contact resistance between Au electrodes and the single crystals. The lowest contact resistivity was obtained by forming Au electrodes on the air-cleaved surface of the Bi 2 Sr 2 CaCu 2 O y single crystal, which is nearly equivalent to a clean surface. X-ray photoelectron spectroscopy results indicated that the contact resistances of the specimens were sensitive to the chemical bond natures of the constituent elements on Bi 2 Sr 2 CaCu 2 O y single crystal surfaces.