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Spin textures, screening, and excitations in dirty quantum Hall ferromagnets
S Rapsch1, J T Chalker, D K K Lee
1Theoretical Physics, Oxford University, Oxford OX1 3NP, United Kingdom.
Physical Review Letters
|January 22, 2002
Summary
We investigated quantum Hall ferromagnets with disorder. A phase transition occurs from a ferromagnet to a spin glass as disorder strength increases, driven by electrostatic impurities.
Area of Science:
- Condensed matter physics
- Quantum magnetism
Background:
- Quantum Hall ferromagnets exhibit complex magnetic behavior.
- Random electrostatic impurity potentials significantly influence electronic systems.
Purpose of the Study:
- To investigate the ground state properties of quantum Hall ferromagnets under disorder.
- To determine the conditions for a phase transition from ferromagnetic to spin glass states.
Main Methods:
- Utilizing a classical nonlinear sigma model.
- Employing analytical estimates and numerical simulations.
- Analyzing ground-state response functions and excitations.
Main Results:
- Disorder strength and filling factor deviation drive a zero-temperature phase transition.
- Systems transition from ferromagnetic to spin glass states with increasing disorder.
- Spin configuration distortions are necessary for impurity potential screening.
Conclusions:
- The interplay between disorder and electron interactions dictates the magnetic ground state.
- A novel disorder-driven phase transition is identified in these systems.