Electron spin polarization by isospin ordering in correlated two-layer quantum Hall systems

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Materials Science

Background:

• Two-dimensional electron systems (2DES) are crucial for understanding quantum phenomena.
• Electron spin polarization is a key property in spintronics and quantum computing.
• Interlayer interactions in multi-layer 2DES can lead to novel correlated states.

Purpose of the Study:

• To investigate the enhancement of electron spin polarization in a correlated two-layer 2DES.
• To determine the conditions under which spin polarization is maximized.
• To understand the role of interlayer Coulomb correlations and their impact on competing quantum states.

Main Methods:

• Utilized resistively detected nuclear magnetic resonance (R-NMR).
• Studied a two-layer, two-dimensional electron system.
• Analyzed behavior at a total Landau level filling factor of 1.

Main Results:

• Observed maximized electron spin polarization in the two-layer system.
• Demonstrated that spontaneous isospin ferromagnetic order, driven by interlayer Coulomb correlations, maximizes spin polarization.
• Showed that this correlation-driven polarization dominates over single-layer fractional quantum Hall states, even with electron density imbalances.

Conclusions:

• Interlayer Coulomb correlations are essential for achieving high electron spin polarization in multi-layer 2DES.
• The spontaneous isospin ferromagnetic state is a powerful mechanism for spin polarization.
• Findings have implications for designing novel electronic devices and understanding complex quantum systems.