Superconductor films on semiconductor substrates have drawn much attention recently since the derived superconductor-based electronics have been shown to be promising for future data processing and storage technologies. By growing atomically uniform single-crystal epitaxial Pb films of several nanometers thick on Si wafers to form a sharp superconductor-semiconductor heterojunction, we have obt...

We describe experimental signatures of Majorana fermion edge states, which form at the interface between a superconductor and the surface of a topological insulator. If a lead couples to the Majorana fermions through electron tunneling, the Majorana fermions induce resonant Andreev reflections from the lead to the grounded superconductor. The linear tunneling conductance is 0 (2e(2)/h) if there...

Using state-of-the-art analytic techniques for extracting a singularity from a complex field, we can visualize the vortices in the largest time-dependent Ginsburg Landau simulation of a superconductor performed to date. Our visualization reveals the internal dynamics of the vortices in the superconductor, explaining the cause of a voltage spike in the electro-magnetic response of the system. Th...

Double tunneling junctions of ferromagnet-superconductor-ferromagnet electrodes (FSF) show a jump in the conductance when a parallel magnetic field reverses the magnetization of one of the ferromagnetic electrodes. This change is generally attributed to the spin-valve effect or to pair breaking in the superconductor because of spin accumulation. In this paper it is shown that the Meservey-Tedro...

We present a time-reversal invariant s-wave superconductor supporting Majorana edge modes. The multiband character of the model together with spin-orbit coupling are key to realizing such a topological superconductor. We characterize the topological phase diagram by using a partial Chern number sum, and show that the latter is physically related to the parity of the fermion number of the time-r...

The quasiparticle local density of states ~LDOS! is studied in clean normal-metal–superconductor ~NS! and superconductor–normal-metal–superconductor ~SNS! junctions with increasing transverse size, from quasione-dimensional to three-dimensional. It is shown that finite transverse dimensions are related to pronounced effects in the LDOS, such as fast oscillations superimposed on the quasiparticl...

The thermal conductivity kappa of the layered s-wave superconductor NbSe2 was measured down to T(c)/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H(c1) and one with highly delocalized quasiparticle excitations at higher fields. The two associated length scales are naturally explained as multiband superconductivity,...

We calculate the tunneling conductance spectra of a normal metal / insulator / triplet superconductor from the reflection amplitudes using the Blonder-Tinkham-Klapwijk (BTK) formula. For the triplet superconductor we assume one special p-wave order parameter having line nodes and two two dimensional f -wave order parameters with line nodes breaking the time-reversal symmetry. Also we examine no...

Cryogenic scanning tunneling microscopy has been used as a local probe of the superconducting proximity effect across a normal metal–superconductor interface of a short coherence length superconductor. Both the topography and the local electronic density of states were measured on a superconducting NbSe 2 crystal decorated with nanometer-size Au islands. The presence of a quasiparticle bound st...

The Josephson effect in p-wave superconductor/diffusive normal metal/p-wave superconductor junctions is studied theoretically. Amplitudes of Josephson currents are several orders of magnitude larger than those in s-wave junctions. Current-phase (J-phi) relations in low temperatures are close to those in ballistic junctions such as J proportional to sin(phi/2) and J proportional to phi even in t...