Transport across a junction of topological insulators and a superconductor

Abstract

We study transport across a line junction lying between two orthogonal topological insulator surfaces and a superconductor which can have either s-wave (spin-singlet) or p-wave (spin-triplet) pairing symmetry. We present a formalism for studying the effect of a general time-reversal invariant barrier at the junction and show that such a barrier can be completely described by three arbitrary parameters. We compute the charge and the spin conductance across such a junction and study their behaviors as a function of the bias voltage applied across the junction and the three parameters used to characterize the barrier. We find that the presence of topological insulators and a superconductor leads to both Dirac and Schrodinger-like features in charge and spin conductances. We discuss the effect of bound states on the superconducting side of the barrier on the conductance; in particular, we show that for triplet p-wave superconductors such a junction may be used to determine the spin state of its Cooper pairs. Our study reveals that there is a non-zero spin conductance for some particular spin states of the triplet Cooper pairs; this is an effect of the topological insulators which break the spin rotation symmetry. Finally, we find an unusual satellite peak (in addition to the usual zero bias peak) in the spin conductance for p-wave symmetry of the superconductor order parameter.

16 pages, 9 figures

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Cited by in corpus (16)

• Superconducting proximity effect in three-dimensional topological insulators in the presence of a magnetic field
• Josephson junctions of multiple superconducting wires
• Chiral nodes and oscillations in the Josephson current in Weyl semimetals
• Enhancement of crossed Andreev reflection in normal-superconductor-normal junction of thin topological insulator
• Edge states of a three-dimensional topological insulator
• Crossed Andreev reflection in collinear $p$-wave magnet/triplet superconductor junctions
• Enhancement of crossed Andreev reflection in a Kitaev ladder connected to normal metal leads
• Finite transverse conductance in topological insulators under an applied in-plane magnetic field
• Confining electrons on a topological insulator surface using potentials and a magnetic field
• Ab initio study of nontrivial topological phases in corundum structured $($M${}_2$O${}_3)/($Al${}_2$O${}_3{)}_5$ multilayers
• Scattering in quantum wires and junctions of quantum wires with edge states of quantum spin Hall insulators
• Transport across a system with three p-wave superconducting wires: effects of Majorana modes and interactions
• Identifying Majorana bound states at quantum spin Hall edges using a metallic probe
• Tunable Majorana corner modes by orbital-dependent exchange interaction in a two-dimensional topological superconductor
• Transport in a thin topological insulator with potential and magnetic barriers
• Symmetry-protected topological wire in a topological vacuum