Local density of states in clean two-dimensional superconductor--normal metal--superconductor heterostructures

Abstract

Motivated by recent advances in the fabrication of Josephson junctions in which the weak link is made of a low-dimensional non-superconducting material, we present here a systematic theoretical study of the local density of states (LDOS) in a clean 2D normal metal (N) coupled to two s-wave superconductors (S). To be precise, we employ the quasiclassical theory of superconductivity in the clean limit, based on Eilenberger's equations, to investigate the phase-dependent LDOS as function of factors such as the length or the width of the junction, a finite reflectivity, and a weak magnetic field. We show how the the spectrum of Andeeev bound states that appear inside the gap shape the phase-dependent LDOS in short and long junctions. We discuss the circumstances when a gap appears in the LDOS and when the continuum displays a significant phase-dependence. The presence of a magnetic flux leads to a complex interference behavior, which is also reflected in the supercurrent-phase relation. Our results agree qualitatively with recent experiments on graphene SNS junctions. Finally, we show how the LDOS is connected to the supercurrent that can flow in these superconducting heterostructures and present an analytical relation between these two basic quantities.

14 pages, 9 figure, submitted to Physical Review

References in corpus (9)

• Bipolar supercurrent in graphene
• Tunable Supercurrent Through Semiconductor Nanowires
• Phase controlled superconducting proximity effect probed by tunneling spectroscopy
• Transport Through Andreev Bound States in a Graphene Quantum Dot
• Signature of magnetic-dependent gapless odd frequency states at superconductor/ferromagnet interfaces
• Pairing symmetry conversion by spin-active interfaces in superconducting junctions
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Cited by in corpus (2)

• Phase-dependent dissipation and supercurrent of a graphene-superconductor ring under microwave irradiation
• SNS Junctions along the BCS-BEC Crossover