Scanning Tunneling Spectroscopy Sensitive to Layer Structure of BSCCO

• Authors: M. Aleszkiewicz , P. Aleszkiewicz , J. Raułuszkiewicz
• Languages of publication: EN

Abstracts

EN

Scanning tunneling microscopy images and scanning tunneling spectroscopy characteristics were measured at 4.2 K in liquid helium bath on the cleaved in air a-b surface of Bi_{2}Sr_{2}CaCu_{2}O_{8} (BSCCO-2212). Electronic densities of states and superconductivity parameters Δ and Γ evaluated from dI/dV characteristics depend on tip-sample distance s: with shortening of the distance s superconducting gap structure becomes more distinct, i.e. Δ increases and Γ decreases. We explain this phenomenon as a non-vacuum tunneling, where for longer s tunneling electrons reach only the surface contamination layer on non-metallic BiO top-surface layer, whereas for shorter s tunneling electrons penetrate also deeper lying CuO layers reflecting their superconducting properties. The dependence of Δ on s is evaluated. This result allows to understand better the non-vacuum scanning tunneling microscopy imaging: by adjusting properly the tip-sample distance one can select suitable local density of states contributing dominantly to the scanning tunneling microscopy images taken on BSCCO.

Keywords

EN

61.16.Ch; 68.65.+g; 74.72.Hs

• Journal: Acta Physica Polonica A
• Year: 1997
• Volume: 91
• Issue: 3
• Pages: 597-604

Dates

published

1997-03

received

1996-08-07

(unknown)

1996-12-16

Contributors

author

M. Aleszkiewicz

• Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland

author

P. Aleszkiewicz

• Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland

author

J. Raułuszkiewicz

• Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland