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Updated: Oct 26, 2025
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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
10.1K
Two-dimensional spin models with macroscopic degeneracy
1Institute of Biochemical Physics of RAS, Kosygin Street 4, 119334 Moscow, Russia.
Summary
This study explores anisotropic spin-1/2 models on 2D lattices, revealing that bound magnon complexes significantly contribute to ground state degeneracy and residual entropy in competing magnetic interactions.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
- Statistical Mechanics
Background:
- Anisotropic spin-1/2 models exhibit complex magnetic behaviors due to competing ferro- and antiferromagnetic interactions.
- Lattices with corner-sharing triangles, such as Tasaki and kagome, are known for geometric frustration and exotic ground states.
- Macroscopic ground state degeneracy in zero magnetic field is a key characteristic of certain frustrated magnetic systems.
Purpose of the Study:
- To investigate the ground state properties of anisotropic spin-1/2 models on 2D Tasaki and kagome lattices.
- To analyze the role of competing magnetic interactions in generating macroscopic ground state degeneracy.
- To quantify the contribution of magnons and bound magnon complexes to the ground state degeneracy and residual entropy.
Main Methods:
- Utilized a class of anisotropic spin-1/2 models with competing interactions.
- Employed an exact wave function approach with an arrow configuration representation on 2D lattices.
- Compared theoretical estimates with results from exactly solved models to validate accuracy.
Main Results:
- Identified conditions for macroscopic ground state degeneracy in zero magnetic field.
- Demonstrated that the ground state manifold includes isolated magnons and bound magnon complexes.
- Showed that the proposed method estimates ground state degeneracy with exponential accuracy.
Conclusions:
- Bound magnon complexes are the primary contributors to the ground state degeneracy and residual entropy in these models.
- The exact wave function approach provides a highly accurate method for determining ground state degeneracy.
- Understanding these complex magnetic states is crucial for developing novel quantum materials and devices.
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