Colossal Orbital Edelstein Effect in Noncentrosymmetric Superconductors

Area of Science:

• Condensed Matter Physics
• Solid-State Physics
• Quantum Materials

Background:

• Superconductors lacking inversion symmetry exhibit Edelstein effects, where supercurrents induce magnetization.
• Understanding the interplay of spin and orbital moments in magnetoelectric phenomena is crucial.

Purpose of the Study:

• To investigate the orbital nature of magnetoelectric effects in spin-singlet superconductors with Rashba coupling.
• To quantify and characterize the supercurrent-induced orbital magnetization.

Main Methods:

• Theoretical analysis of electron spin and orbital moments in superconductors.
• Investigating the role of Rashba coupling and Fermi level proximity to band crossings.
• Exploring the impact of superconducting phase inhomogeneities.

Main Results:

• Supercurrent-induced orbital magnetization is over an order of magnitude larger than spin magnetization, resulting in a colossal magnetoelectric effect.
• Orbital magnetization is sign-tunable, dependent on Fermi level position relative to band structure features.
• Superconducting phase inhomogeneities lead to spatial modulations of the Edelstein signal.

Conclusions:

• Orbital magnetoelectric phenomena are dominant in these superconductors and possess distinct signatures for detection.
• These findings are robust to self-consistent treatment of the superconducting order parameter.
• The orbital-dominated magnetoelectric effect is expected in multiorbital superconductors lacking inversion symmetry.