Srikanth, H and Raychaudhuri, AK (1991) Effect of surface on the conductance characteristics of Au‐Bi2Sr2CaCu2O8+δ (single crystal) point contact junctions. In: Journal of Applied Physics, 70 (12). pp. 7478-7483.
Effect_of_surface.....pdf - Published Version
Restricted to Registered users only
Download (1340Kb) | Request a copy
We report the effect of surface treatments on the dynamic conductance curves (G=dI/dV‐V) of Au‐Bi2Sr2CaCu2O8+δ (single crystal) point contact junctions of variable junction conductances (100 mS≳G≳100 μS). We find that if the crystal surface is cleaved freshly just prior to making contacts, all irreproducible sharp multiple features often observed in tunneling data of Bi(2212) oxide superconductors disappear. If the cleaved crystal surfaces are left under ambient conditions for a few days and the tunneling experiments are repeated, these multiple features reappear. We also find that if the current in the junction is made to pass predominantly through the bulk (and not along the surface), gap features are sharper. The observed conductance curves are fitted to a modified model [G. E. Blonder et al., Phys. Rev. B 25, 4515 (1982)] and estimated gap values are Δ≂28 to 30 meV corresponding to the ratio 2Δ/kBTc ≂ 7.5 with lifetime broadening Γ/Δ≂0.2. We conclude that the sharp multiple features observed in Bi(2212) tunneling curves has no intrinsic origin in the bulk and they arise from the surface only.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to American Institute of Physics.|
|Department/Centre:||Division of Physical & Mathematical Sciences > Physics|
|Date Deposited:||29 Dec 2011 05:03|
|Last Modified:||29 Dec 2011 05:03|
Actions (login required)