Related Experiment Video
Updated: May 31, 2026
09:00
Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
Spin-Galvanic Response to Nonequilibrium Spin Injection in Superconductors with Spin-Orbit Coupling
I V Tokatly1,2,3, Yao Lu4, F Sebastian Bergeret3,5
1Universidad del País Vasco, Nano-Bio Spectroscopy Group, Departamento de Polímeros y Materiales Avanzados, 20018 Donostia-San Sebastián, Basque Country, Spain.
Physical Review Letters
|May 29, 2026
Summary
Nonequilibrium spin injection into superconductors can create anomalous supercurrents and phase gradients. This effect, enhanced by superconductivity, explains experimental observations and predicts new spin-charge coupling phenomena.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Superconductivity
Background:
- Superconducting devices are crucial for quantum technologies.
- Understanding spin injection in superconductors is key to novel functionalities.
- Previous theories predicted limited spin injection below the superconducting gap.
Purpose of the Study:
- To investigate anomalous supercurrent generation via nonequilibrium spin injection.
- To explore the role of superconductivity in enhancing spin injection.
- To explain experimental observations and predict new phenomena in spin-charge coupling.
Main Methods:
- Theoretical modeling of spin injection into superconductors.
- Analysis of quasiparticle density of states near the superconducting gap.
- Investigating spin-charge coupling effects in superconducting systems.
Main Results:
- Nonequilibrium spin injection generates anomalous supercurrents and phase gradients below the superconducting gap.
- Superconductivity enhances spin injection due to quasiparticle density of states.
- The mechanism does not require breaking time-reversal symmetry.
Conclusions:
- Provides a mechanism for observed spin injection in superconductors.
- Predicts novel effects like electrical control of phase gradients.
- Suggests broad testability in various superconducting materials and structures.
More Related Videos
Related Concept Videos
01:08NMR Spectroscopy: Spin–Spin Coupling
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:17Spin–Spin Coupling: One-Bond Coupling
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
01:03Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...