Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Iron-based superconductors exhibit complex magnetic properties.
• Controlling magnetism is key to understanding and manipulating superconductivity.
• Magnetically frustrated systems present unique challenges and opportunities.

Purpose of the Study:

• To investigate a novel mechanism for switching magnetism and superconductivity.
• To explore the role of spin-polarized currents in iron-based superconductors.
• To understand the relationship between magnetic order symmetry and superconductivity.

Main Methods:

• Utilized spin-polarized scanning tunneling microscopy (SPSTM) on single-crystal Sr_{2}VO_{3}FeAs.
• Employed tunneling spectroscopy to characterize magnetic order.
• Compared the effects of spin-polarized versus unpolarized tunneling currents and thermal excitation.

Main Results:

• A spin-polarized tunneling current induced a nontrivial C_{4} (2×2) magnetic order in the Fe layer, distinct from thermal excitation effects.
• The induced C_{4} (2×2) order exhibits characteristics of plaquette antiferromagnetism.
• This induced magnetic order significantly suppresses superconductivity and is erasable by thermal agitation.

Conclusions:

• Demonstrated a new method to switch local magnetic order using spin-polarized currents.
• Established a strong link between the symmetry of magnetic order and superconductivity suppression.
• Suggests a pathway for controlling superconductivity by manipulating magnetic order in iron-based superconductors.