Bi2YbO4Cl: A two-dimensional square-lattice compound with Jeff= 12 magnetic moments
Résumé
The interplay between the quantum effects from low-dimensionality and the spin-orbit coupling leads to exotic ground states with unusual excitations. We report the structural, magnetic, heat capacity, and electronic structure studies of Bi2YbO4Cl, which constitutes a structurally perfect 2D square lattice with rare-earth magnetic Yb3+ ions. The magnetization and heat capacity data analysis confirms that the Yb3+ ion hosts the spin-orbit driven Jeff=12 state at low temperatures. From the fit to the Curie-Weiss law on the magnetic susceptibility data in the low-temperature region, the observed Curie-Weiss temperature is about -1 K, implying an antiferromagnetic (AFM) coupling between the Yb3+ moments. The heat capacity data show the presence of a broad maximum at 0.3 K and the absence of any sharp magnetic anomaly down to 0.09 K, indicating the onset of short-range correlations. Our first-principles calculations based on density functional theory provide further insight into the role of the microscopic parameters. In particular, it points out the crucial role of spin-orbit coupling in driving both the Jeff=12 state as well as the antiferromagnetic interaction between the nearest-neighbor Yb3+ moments that is consistent with experimental results. The total energy calculations suggest an easy-axis (out-of-plane) anisotropy of the spins.
Mots clés
- Orbits
- Magnetic susceptibility
- Magnetic moments
- Ground state
- Electronic structure
- Antiferromagnetism
- Quantum theory
- Density functional theory
- Yb3+ ions
- Two dimensional square lattice
- Square lattices
- Spin-orbit couplings
- Spin orbits
- Rare-earths
- Quantum effects
- Low dimensionality
- Heat-capacity data
- Electronic.structure
- Temperature
- Specific heat
- Rare earths