Unveiling the S=3/2 Kitaev honeycomb spin liquids

Area of Science:

• Condensed Matter Physics
• Quantum Magnetism
• Topological Phases of Matter

Background:

• The Kitaev honeycomb model (KHM) is a key theoretical framework for studying quantum spin liquids (QSLs).
• Understanding spin-3/2 systems offers new avenues beyond the well-studied spin-1/2 counterparts.
• Gauge field interactions are crucial for realizing exotic QSL states.

Purpose of the Study:

• To investigate the ground-state properties of the S=3/2 Kitaev honeycomb model.
• To map out the phase diagram, including gapped and gapless quantum spin liquid phases.
• To explore the effects of single ion anisotropy on the QSL state.

Main Methods:

• Utilizing an SO(6) Majorana representation for spin-3/2 operators.
• Developing an exact representation of conserved plaquette fluxes using static Z2 gauge fields.
• Applying parton mean-field theory to the interacting matter fermion sector.
• Employing perturbation theory to study anisotropy effects.

Main Results:

• An exact representation of plaquette fluxes was found, analogous to the S=1/2 KHM.
• A phase diagram featuring gapped and gapless QSLs was uncovered.
• Parton mean-field theory results quantitatively matched numerical simulations.
• The addition of [001] single ion anisotropy (SIA) bridges the gapless Dirac QSL to the S=1/2 KHM.
• A chiral QSL phase emerges under weak [111] SIA.

Conclusions:

• The SO(6) Majorana representation provides a powerful tool for analyzing spin-3/2 QSLs.
• The S=3/2 KHM hosts rich QSL physics, including gapless and gapped phases.
• Anisotropy plays a critical role in tuning QSL properties and realizing emergent phases.