Current fluctuations in unconventional superconductor junctions with impurity scattering
arXiv:1703.02900 · doi:10.1103/PhysRevB.95.224502
Abstract
The order parameter of bulk two-dimensional superconductors is classified as nodal, if it vanishes for a direction in momentum space, or gapful if it does not. Each class can be topologically nontrivial if Andreev bound states are formed at the edges of the superconductor. Non-magnetic impurities in the superconductor affect the formation of Andreev bound states and can drastically change the tunneling spectra for small voltages. Here, we investigate the mean current and its fluctuations for two-dimensional tunnel junctions between a normal-metal and unconventional superconductors by solving the quasi-classical Eilenberger equation self-consistently, including the presence of non-magnetic impurities in the superconductor. As the impurity strength increases, we find that superconductivity is suppressed for almost all order parameters since (i) at zero applied bias, the effective transferred charge calculated from the noise-current ratio tends to the electron charge and (ii) for finite bias, the current-voltage characteristics follows that of a normal state junction. There are notable exceptions to this trend. First, gapful nontrivial (chiral) superconductors are very robust against impurity scattering due to the linear dispersion relation of their surface Andreev bound states. Second, for nodal nontrivial superconductors, only p_x-wave pairing is almost immune to the presence of impurities due to the emergence of odd-frequency s-wave Cooper pairs near the interface. Owing to their anisotropic dependence on the wave vector, impurity scattering is an effective pair breaking mechanism for the rest of nodal superconductors. All these behaviors are neatly captured by the noise-current ratio, providing a useful guide to find experimental signatures for unconventional superconductivity.
10 pages, 4 figures
References in corpus (16)
- Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
- Classification of topological insulators and superconductors in three spatial dimensions
- Chiral P-Wave Order in Sr_2RuO_4
- Theory of the proximity effect in junctions with unconventional superconductors
- Odd-frequency pairing in normal metal/superconductor junctions
- Topological properties of spin-triplet superconductors and the Fermi surface topology in the normal state
- Anomalous Andreev bound state in non-centrosymmetric superconductors
- Majorana Fermions and Odd-frequency Cooper Pairs in a Nano Wire
- Surface density of states and topological edge states in non-centrosymmetric superconductors
- Topological Order and Non-Abelian Statistics in Noncentrosymmetric s-Wave Superconductors
- Vanishing edge currents in non--wave topological chiral superconductors
- Orbital Angular Momentum and Spectral Flow in Two Dimensional Chiral Superfluids
- Unconventional Superconductivity in Double Quantum Dots
- Symmetry Protected Topological Superfluid He-B
- Anomalous Proximity Effect and Theoretical Design for its Realization
- Anomalous surface states at interfaces in p-wave superconductors
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