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Pseudospin Quantum Hall Ferromagnetism Probed by Electron Spin Resonance
A V Shchepetilnikov1, A R Khisameeva1, S A Andreeva1,2
1<a href="https://ror.org/00ezjkn15">Osipyan Institute of Solid State Physics RAS</a>, 142432 Chernogolovka, Moscow district, Russia.
Physical Review Letters
|September 13, 2024
Summary
This study uses electron spin resonance to investigate pseudospin ferromagnetism in AlAs quantum wells. Researchers observed ferromagnetic phase transitions at quantum Hall effect filling factors, demonstrating their pseudospin nature.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
Background:
- Pseudospin is a two-component degree of freedom labeling degenerate energy minima in momentum space.
- Mechanical strain in AlAs quantum wells creates a "Zeeman" splitting between pseudospin states.
Purpose of the Study:
- Investigate pseudospin ferromagnetism using electrically detected electron spin resonance.
- Analyze ferromagnetic phase transitions at quantum Hall effect integer filling factors.
Main Methods:
- Electrically detected electron spin resonance in a wide AlAs quantum well.
- Independent measurement of electron spin resonances from in-plane valleys due to spin splitting anisotropy.
- Analysis of resonance amplitudes during tilted magnetic field.
Main Results:
- Observed and analyzed ferromagnetic phase transitions at integer filling factors.
- Demonstrated the pseudospin nature of these transitions.
- Independently measured electron spin resonances from two in-plane valleys.
Conclusions:
- Pseudospin ferromagnetism plays a key role in quantum Hall effect phase transitions.
- Electron spin resonance is a powerful tool for probing pseudospin phenomena.
- The study provides insights into the complex interplay of spin, pseudospin, and magnetic fields in 2D electron systems.
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