Andreev reflection at the normal-metal/heavy-fermion superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>Ce</mml:mi><mml:mi>Co</mml:mi><mml:msub><mml:mi>In</mml:mi><mml:mo>5</mml:mo></mml:msub></mml:mrow></mml:math>interface

Abstract

The dynamic conductance of the heavy-fermion superconductor CeCoIn$_5$ is measured by point-contact spectroscopy as a function of temperature from 60 K down to 400 mK. The contact between the gold tip and the single-crystal is shown to be in the Sharvin limit with the enhanced sub-gap conductance arising from Andreev reflection. The zero-bias conductance data are best fit using the extended Blonder-Tinkham-Klapwijk model with a d-wave superconducting order parameter. A fit to the full conductance curve at 400 mK indicates strong coupling ($2\Delta(0)/k_\textrm{B}T_\textrm{c} = 4.6$) and quantifies the suppressed Andreev reflection signal, which is a signature of normal-metal/heavy-fermion superconductor junctions. Possibilites for theoretical modeling to account for the suppressed Andreev conductance are suggested.

Locations

• arXiv (Cornell University) - View - PDF
• DataCite API - View
• Physical Review B - View