Disorder-Driven Spin-Orbital Liquid Behavior in the Ba3XSb2O9 Materials
Andrew Smerald1, Frédéric Mila1
1Institut de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Physical Review Letters
|November 10, 2015
Summary
Researchers modeled complex Ba(3)XSb(2)O(9) materials, revealing fractal X(2+) clusters that explain orphan spins. This disorder may promote spin-orbital liquid physics in these frustrated magnetic materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Magnetism
Background:
- The Ba(3)XSb(2)O(9) family exhibits potential spin and spin-orbital liquid behavior.
- Complex lattice structures arise from charged X(2+)-Sb(5+) dumbbells with dual orientations.
Purpose of the Study:
- To model the lattice structure of Ba(3)XSb(2)O(9) materials.
- To understand the origin of "orphan spins" and their role in potential spin-orbital liquid physics.
Main Methods:
- Monte Carlo simulations of a frustrated model of charged dumbbells on a triangular lattice.
- Analysis of long-range Coulomb interactions.
- Comparison of simulated structure factor with x-ray diffraction data.
Main Results:
- A freezing temperature (T(frz)) was identified where simulations match experimental data.
- A fractal "branching" structure of superexchange-linked X(2+) clusters with dimension d(f)=1.90 was observed at T(frz).
- This fractal structure provides an explanation for the presence of orphan spins.
Conclusions:
- Dumbbell disorder in Ba(3)XSb(2)O(9) materials can lead to fractal cluster formation.
- This disorder is a plausible mechanism for promoting spin-orbital resonant states with delocalized orphan spins.
- The findings offer insights into the complex physics of frustrated magnetic materials.
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