Spin Dynamics in the Dirac U(1) Spin Liquid YbZn_{2}GaO_{5}

Area of Science:

• Condensed matter physics
• Quantum magnetism
• Materials science

Background:

• Quantum spin liquids (QSLs) are exotic states of matter with entangled spins.
• YbZn₂Ga O₅ is a candidate material for realizing QSL behavior due to its structural properties.
• Understanding the ground state of such materials is crucial for quantum computing and fundamental physics.

Purpose of the Study:

• To investigate the magnetic ground state of YbZn₂Ga O₅.
• To determine if YbZn₂Ga O₅ exhibits a quantum spin liquid state.
• To characterize the spin dynamics and magnetic fluctuations within the material.

Main Methods:

• Pulsed-field magnetometry at low temperatures (0.5 K) to measure magnetization.
• Zero-field and longitudinal-field muon spin spectroscopy (μSR) down to milliKelvin temperatures.
• Analysis of magnetization saturation and muon spin relaxation rates to probe magnetic properties.

Main Results:

• Magnetization saturates near 15 T with a corrected moment of 2.1(1)μB, indicating the presence of magnetic moments.
• Zero-field μSR data show a dynamic ground state and no long-range magnetic order down to milliKelvin temperatures.
• Longitudinal-field μSR experiments reveal spin dynamics with field dependence consistent with a U(1) Dirac quantum spin liquid model.

Conclusions:

• YbZn₂Ga O₅ is a strong candidate for a quantum spin liquid state.
• The experimental results support the U(1) Dirac QSL as a plausible description of the ground state.
• The absence of magnetic order and observed spin dynamics are key indicators of QSL behavior in this material.