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Itinerant electron-driven chiral magnetic ordering and spontaneous quantum Hall effect in triangular lattice models
1Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review Letters
|November 13, 2008
Summary
We discovered a new chiral magnetic ordering in triangular lattice models. This ordering can lead to a spontaneous quantum Hall effect without an external magnetic field.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Theoretical Physics
Background:
- The Kondo Lattice and Hubbard models are fundamental for understanding correlated electron systems.
- Triangular lattices exhibit unique geometric frustration, influencing magnetic ordering.
- Chiral magnetic ordering is a complex phenomenon with potential for novel electronic properties.
Purpose of the Study:
- Investigate magnetic ordering in Kondo Lattice and Hubbard models on a triangular lattice.
- Explore the emergence of chiral magnetic states.
- Determine the conditions for spontaneous quantum Hall effect.
Main Methods:
- Mean-field theory analysis.
- Investigation of band filling factor effects, specifically at 3/4 filling.
- Analysis of Fermi surface nesting properties.
Main Results:
- Identified a naturally occurring noncoplanar chiral magnetic ordering in rotationally invariant models.
- This ordering arises as a weak-coupling instability at 3/4 band filling due to Fermi surface nesting.
- Chirality persists to finite temperatures, independent of long-range magnetic order, inducing a spontaneous quantum Hall effect.
Conclusions:
- The triangular lattice provides a platform for exotic chiral magnetism.
- Chiral ordering and spontaneous quantum Hall effect are robust phenomena in these models.
- Findings offer insights into novel quantum states in correlated electron systems.
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