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Directional Localization from a Magnetic Field in Moiré Systems
Nisarga Paul1, Philip J D Crowley1, Liang Fu1
1Department of Physics, <a href="https://ror.org/042nb2s44">Massachusetts Institute of Technology</a>, Cambridge, Massachusetts, USA.
Physical Review Letters
|July 1, 2024
Summary
We discovered highly directional electrical conductivity in strained moiré materials under magnetic fields. This directional conductivity, or anisotropic conductivity, switches orientation with changes in magnetic field or strain.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Moiré materials offer a tunable platform for exploring emergent electronic phenomena.
- Understanding electron behavior in these materials under external fields is crucial for novel device applications.
Purpose of the Study:
- To investigate the electronic properties of strained moiré materials in a uniform magnetic field.
- To predict and explain the emergence of highly anisotropic electrical conductivity.
Main Methods:
- Theoretical study of strained moiré materials subjected to a uniform magnetic field.
- Utilized an effective one-dimensional quasiperiodic Aubry-André-Harper-like model.
- Employed a complementary semiclassical picture for analysis.
Main Results:
- Predicted highly anisotropic electrical conductivity in strained moiré materials.
- Observed a switching of the conductivity's easy axis with variations in magnetic field or strain.
- Attributed the anisotropy to one-dimensional localization of electron wave functions via quantum interference.
Conclusions:
- The study reveals a novel electronic phenomenon: directional localization in moiré materials.
- This anisotropic conductivity is predicted to be observable in realistic experimental conditions.
- The findings are relevant for both strained and unstrained systems with anisotropic Fermi surfaces.
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