Probing the topological band structure of diffusive multiterminal Josephson junction devices with conductance measurements

Abstract

The energy of an Andreev bound state in a clean normal metal in contact with two superconductors disperses with the difference $\Delta \varphi$ in the superconducting phase between the superconductors in much the same way as the energies of electrons in a one-dimensional crystal disperse with the crystal momentum $k$ of the electrons. A normal metal with $n$ superconductors maps on to a $n-1$ dimensional crystal, each dimension corresponding to the phase difference ${\varphi }_i$ between a specific pair of superconductors. The resulting band structure as a function of the phase differences $\{\Delta {\varphi }_i\}$ has been proposed to have a topological nature, with gapped regions characterized by different Chern numbers separated by regions where the gap in the quasiparticle spectrum closes. A similar complex evolution of the quasiparticle spectrum with $\{\Delta {\varphi }_i\}$ has also been predicted for diffusive normal metals in contact with multiple superconductors. Here we show that the variation of the density of states at the Fermi energy of such a system can be directly probed by relatively simple conductance measurements, allowing rapid characterization of the energy spectrum.

4 pages, 4 figures

References in corpus (5)

• Phase controlled superconducting proximity effect probed by tunneling spectroscopy
• Single fermion manipulation via superconducting phase differences in multiterminal Josephson junctions
• Topological Andreev bands in three-terminal Josephson junctions
• Quantitative measurements of the thermal resistance of Andreev interferometers
• Non-Abelian monopoles in the multiterminal Josephson effect

Cited by in corpus (4)

• Mapping the topological proximity-induced gap of multiterminal Josephson junctions
• Full tomography of topological Andreev bands in graphene Josephson junctions
• Nonequilibrium Andreev resonances in ballistic graphene Andreev interferometers
• Multiterminal Josephson junctions with tunable topological properties