Abstract
We propose a model for a superconductor where both spin-singlet and chiral triplet pairing amplitudes can coexist. By solving the Bogoliubov–de Gennes equations with a general pair potential that accounts for both spin states we study experimental signatures of normal metal and superconductor hybrids. The interplay between the spin-singlet and triplet correlations manifests in the appearance of two effective gaps. When the amplitude of the spin-triplet component is stronger than that of the spin singlet, a topological phase transition into a nontrivial regime occurs. As a result, the normal metal–superconductor conductance evolves from a conventional gap profile onto an unconventional zero-bias peak. Additionally, in the topologically nontrivial phase, Andreev bound states formed at Josephson junctions present zero-energy modes; the number of those modes depends on the relative chirality of the junction. Finally, we present results for the current-phase relation and the temperature dependence of the Josephson critical current within both topological phases for several system parameters.
- Received 27 June 2014
- Revised 5 August 2014
DOI:https://doi.org/10.1103/PhysRevB.90.085438
©2014 American Physical Society