Continuum Excitations in a Spin Supersolid on a Triangular Lattice

Area of Science:

• Condensed Matter Physics
• Quantum Magnetism
• Materials Science

Background:

• Triangular lattice magnets exhibit complex magnetic behaviors due to competing interactions.
• Understanding spin correlations is crucial for characterizing exotic magnetic states.

Purpose of the Study:

• To investigate spin correlations and low-energy excitations in the easy-axis XXZ triangular lattice magnet K_{2}Co(SeO_{3})_{2}.
• To explore the effects of magnetic fields on the magnetic order and excitation spectrum.

Main Methods:

• Magnetic measurements
• Thermodynamic analysis
• Neutron diffraction
• Inelastic neutron scattering

Main Results:

• Quasi-2D "supersolid" magnetic order was observed at zero field.
• The low-energy excitation spectrum showed a broad multiparticle continuum, lacking sharp modes.
• Application of a weak magnetic field induced an m=1/3 fractional magnetization plateau.
• Sharp spin wave modes were restored in the presence of the magnetic field.

Conclusions:

• The observed behavior at zero field can be partially explained by spin wave decay.
• Excitation minima suggest that spinon descriptions may be more suitable.
• The findings indicate a potential proximity to a Dirac spin liquid state.