Abstract
The Mott insulator α-RuCl3 has generated great interest in the community due to its possible field-induced Kitaev quantum spin liquid state. Despite enormous effort spent trying to obtain the form of the low-energy Hamiltonian, there is currently no agreed upon set of parameters which is able to explain all of the data. A key piece of missing information lies in the determination of the magnetic form factor of Ru3+, particularly for a true quantitative treatment of inelastic neutron scattering data. Here we present the experimentally derived magnetic form factor of Ru3+ in the low spin 4d5 state using polarized neutron diffraction within the paramagnetic regime on high-quality single crystals of α-RuCl3. We observe strong evidence of an anisotropic form factor, expected of the spin-orbit coupled jeff=12 ground state. We model the static magnetization density in increasing complexity from simple isotropic cases, to a multipolar expansion, and, finally, ab initio calculations of the generalized jeff=12 ground state. Comparison of both single ion models and inclusion of Cl- anions support the presence of hybridization of Ru3+ with the surrounding Cl- ligands.
| Original language | English |
|---|---|
| Article number | 104432 |
| Journal | Physical Review B |
| Volume | 109 |
| Issue number | 10 |
| DOIs | |
| State | Published - Mar 1 2024 |
Funding
This research was supported by the U.S. Department of Energy (DOE), Office of Science, National Quantum Information Science Research Centers, Quantum Science Center. Part of this research (T.B.) was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. C.E. was supported by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. DOE, Office of Science, Basic Energy Sciences, Division of Materials, under Contract No. DE-AC36-08GO28308. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Visual representations of the crystal structure shown in this paper were produced using the open source software VESTA . C L.S. is grateful to A. Scheie and F. Ye for many fruitful discussions. This paper has been coauthored by employees of UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). The U.S. government retains, and the publisher, by accepting the article for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this paper, or allow others to do so, for U.S. government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan . This research was supported by the U.S. Department of Energy (DOE), Office of Science, National Quantum Information Science Research Centers, Quantum Science Center. Part of this research (T.B.) was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. C.E. was supported by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. DOE, Office of Science, Basic Energy Sciences, Division of Materials, under Contract No. DE-AC36-08GO28308. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.