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Density-controlled quantum Hall ferromagnetic transition in a two-dimensional hole system.
T M Lu1, L A Tracy2, D Laroche2
1Sandia National Laboratories, Albuquerque, New Mexico, 87185, USA. tlu@sandia.gov.
Scientific Reports
|June 3, 2017
Summary
Researchers demonstrate a gate-controlled quantum Hall ferromagnetic transition in a 2D hole system. This transition, achieved without magnetic fields, paves the way for novel semiconductor applications.
Area of Science:
- Condensed Matter Physics
- Quantum Phenomena
Background:
- Quantum Hall ferromagnetic transitions typically require magnetic fields or pseudo-spin manipulation.
- Controlling spin states is crucial for advanced quantum devices.
Purpose of the Study:
- To achieve a gate-controlled quantum Hall ferromagnetic transition in a conventional 2D system.
- To investigate spin-polarization mechanisms in 2D hole systems.
Main Methods:
- Utilizing a Germanium (Ge) two-dimensional hole system.
- Employing gate voltage to control carrier density and inter-carrier interactions.
- Measuring resistance and analyzing Zeeman splitting to cyclotron gap ratio.
Main Results:
- A gate-controlled ferromagnetic transition was observed at filling factor ν=2 without in-plane magnetic fields.
- The ratio of Zeeman splitting to cyclotron gap increased with decreasing density, exceeding 1 below ~2.4×10^10 cm^-2.
- A resistance peak at the critical density indicated the formation of spin-oriented domains.
Conclusions:
- Gate control enables ferromagnetic transitions in 2D systems, offering an alternative to magnetic field methods.
- This work facilitates the exploration of Majorana modes in low-spin-orbit-coupling semiconductors.
- Demonstrates a novel approach for spin manipulation in quantum Hall systems.
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