Evidence for spin-polarized bound states in semiconductor–superconductor–ferromagnetic-insulator islands
S. Vaitiekėnas, Rubén Seoane Souto, Yu Liu, Peter Krogstrup, Karsten Flensberg, Martin Leijnse, C. M. Marcus
Abstract
We report Coulomb blockade transport studies of semiconducting InAs nanowires grown with epitaxial superconducting Al and ferromagnetic insulator EuS on overlapping facets. Comparing experiment to a theoretical model, we associate cotunneling features in even-odd bias spectra with spin-polarized Andreev levels. Results are consistent with zero-field spin splitting exceeding the induced superconducting gap. Energies of subgap states are tunable on either side of zero via electrostatic gates.
Topics & Concepts
Condensed matter physicsSuperconductivityFerromagnetismCoulomb blockadeBound stateNanowireInsulator (electricity)PhysicsSemiconductorSpin (aerodynamics)CoulombAndreev reflectionSpin polarizationElectronQuantum mechanicsTransistorVoltageOptoelectronicsThermodynamicsPhysics of Superconductivity and MagnetismQuantum and electron transport phenomenaElectronic and Structural Properties of Oxides