Resonant transport through midgap states in voltage-biased Josephson junctions of d-wave superconductors

Abstract

We study theoretically the ac Josephson effect in voltage biased planar junctions of d-wave superconductors. For some orientations of the superconductors a current peak is found at finite voltage in the current-voltage characteristics. We pick out the relevant physical processes and write down an analytical formula for the current which clearly shows how the midgap state acts as a resonance and produces the peak. We present a possible explanation for the zero-bias conductance peak, recently found in experiments on grain boundary junctions of high-temperature superconductors, in terms of resonant transmission through midgap state of quasiparticles undergoing multiple Andreev reflections. We note that within our framework the zero-bias conductance peak appears in rather transparent Josephson junctions of d-wave superconductors.

10 pages, 5 figures, Submitted to a special volume of "Superlattices and Microstructures"

References in corpus (6)

• Observation of Bound Surface States in Grain Boundary Junctions of High Temperature Superconductors
• Andreev Bound States in High Temperature Superconductors
• Influences of broken time-reversal symmetry on the d.c. Josephson effects in d-wave superconductors
• ac Josephson effect in superconducting d-wave junctions
• Superconducting d-wave junctions: The disappearance of the odd ac components
• Multiple Andreev reflections as a transport problem in energy space

Cited by in corpus (2)

• Andreev bound states in high-$T_c$ superconducting junctions
• Multiple Andreev reflections as a transport problem in energy space