TY - JOUR
A1 - Zazunov, Alex
A1 - Iks, Albert
A1 - Alvarado, Miguel
A1 - Levy Yeyati, Alfredo
A1 - Egger, Reinhold
T1 - Josephson effect in junctions of conventional and topological superconductors
JF - Beilstein Journal of Nanotechnology
Y1 - 2018///
VL - 9
SP - 1659
EP - 1676
SN - 2190-4286
M3 - doi:10.3762/bjnano.9.158
N2 - We present a theoretical analysis of the equilibrium Josephson current-phase relation in hybrid devices made of conventional s-wave spin-singlet superconductors (S) and topological superconductor (TS) wires featuring Majorana end states. Using Green’s function techniques, the topological superconductor is alternatively described by the low-energy continuum limit of a Kitaev chain or by a more microscopic spinful nanowire model. We show that for the simplest S–TS tunnel junction, only the s-wave pairing correlations in a spinful TS nanowire model can generate a Josephson effect. The critical current is much smaller in the topological regime and exhibits a kink-like dependence on the Zeeman field along the wire. When a correlated quantum dot (QD) in the magnetic regime is present in the junction region, however, the Josephson current becomes finite also in the deep topological phase as shown for the cotunneling regime and by a mean-field analysis. Remarkably, we find that the S–QD–TS setup can support φ0-junction behavior, where a finite supercurrent flows at vanishing phase difference. Finally, we also address a multi-terminal S–TS–S geometry, where the TS wire acts as tunable parity switch on the Andreev bound states in a superconducting atomic contact.
ER -