Observation of a-b plane gap anisotropy in <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></math><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">Sr</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">CaCu</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">O</mi></mrow><mrow><mn>8</mn></mrow></msub></mrow></math> with a low temperature scanning tunneling microscope

Jeffrey Kane; Qun Chen; K.-W. Ng; H.-J. Tao

doi:10.1103/PhysRevLett.72.128

Observation of a-b plane gap anisotropy in ${Bi}_{2}$ ${Sr}_{2}$ ${CaCu}_{2}$ $O_{8}$ with a low temperature scanning tunneling microscope

Jeffrey Kane, Qun Chen, K.-W. Ng, and H.-J. Tao

Phys. Rev. Lett. 72, 128 – Published 3 January 1994

Abstract

Significant gap anisotropy within the a-b plane of ${Bi}_{2}$ ${Sr}_{2}$ ${CaCu}_{2}$ $O_{8}$ has been observed with a low temperature scanning tunneling microscope. The energy gap is largest along the a-axis direction, with $Δ_{p - p}$ =36.6 meV and decreases gradually to a value of 23 meV along the direction 45° from the a axis. The tunneling data have been fit well using a simple model which assumes a d-wave-pairing energy gap, and allows tunneling in all directions close to the normal of the surface.