Supersolidity in the triangular lattice spin-1/2 XXZ model: a variational perspective

Area of Science:

• Condensed Matter Physics
• Quantum Many-Body Systems
• Statistical Mechanics

Background:

• The spin-1/2 XXZ model on a triangular lattice is a key model for understanding complex magnetic phenomena.
• Investigating the interplay between Ising coupling and kinetic terms is crucial for predicting emergent phases.

Purpose of the Study:

• To determine the variational phase diagram of the spin-1/2 XXZ model on a triangular lattice.
• To characterize supersolid phases arising from frustrated and unfrustrated kinetic terms.

Main Methods:

• Application of long-range Jastrow correlations.
• Utilizing a mean-field spin state approximation.
• Analysis of large lattice systems for arbitrary coupling parameters.

Main Results:

• Identification of a square root(3) x square root(3) supersolid for J(perpendicular) < 0 when J(z)/J(perpendicular) > 4.7.
• Discovery of a distinct square root(3) x square root(3) supersolid for J(perpendicular) > 0 when J(z)/J(perpendicular) >= 1.
• Observation of spontaneous density deviation from half-filling in both supersolid phases.

Conclusions:

• The study provides a comprehensive phase diagram for the spin-1/2 XXZ model on a triangular lattice.
• The predicted supersolid phases show excellent agreement with quantum Monte Carlo and exact solution results.
• The findings contribute to the understanding of exotic quantum phases in frustrated magnetic systems.