Observation of a geometrical resonance effect in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">Bi</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi mathvariant="normal">Sr</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mi mathvariant="normal">Ca</mi><mrow><msub><mrow><mi mathvariant="normal">Cu</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi mathvariant="normal">O</mi></mrow><mrow><mn>8</mn><mo>+</mo><mi>x</mi></mrow></msub></mrow></math></span> break junctions

B. A. Aminov; M. A. Hein; G. Müller; H. Piel; D. Wehler; V. Z. Kresin; Ya. G. Ponomarev; L. Buschmann; L. Winkeler; G. Güntherodt

doi:10.1103/PhysRevB.54.6728

Observation of a geometrical resonance effect in ${Bi}_{2} {Sr}_{2} Ca {Cu}_{2} O_{8 + x}$ break junctions

B. A. Aminov, M. A. Hein, G. Müller, H. Piel, D. Wehler, V. Z. Kresin, Ya. G. Ponomarev, L. Buschmann, L. Winkeler, and G. Güntherodt

Phys. Rev. B 54, 6728 – Published 1 September 1996

Abstract

A periodic structure has been observed in the tunneling characteristics of ${Bi}_{2} {Sr}_{2} Ca {Cu}_{2} O_{8 + x}$ break junctions. The observed structure is explained by the electron-hole interference effect in the surface layer, which produces a periodic structure in the tunneling characteristics. Good qualitative agreement has been obtained between measured data and calculated with Arnold's proximity model characteristics. The observed effect indicates an important role of the proximity effect on surface sensitive properties of high- $T_{c}$ superconductors, and explains the reported discrepancy of energy-gap values for ${Bi}_{2} {Sr}_{2} Ca {Cu}_{2} O_{8 + x}$ .