Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session X50: Orbital Degeneracy Breaking and Emergent Local Symmetry in Transition Metal Compounds
8:00 AM–11:00 AM,
Friday, March 19, 2021
Sponsoring Unit: DCMP
Chair: Simon Kimber, University of Bourgogne
Abstract: X50.00005 : Scattering Signatures of Bond-Dependent Magnetic Interactions*
10:24 AM–11:00 AM
(Oak Ridge National Lab)
(Oak Ridge National Lab)
Robust determination of bond-dependent interactions is key to identifying candidate materials. However, such interactions are challenging to measure experimentally . In this talk, I explore the extent to which bond-dependent interactions can be extracted from diffuse magnetic neutron-scattering data measured in the paramagnetic phase. I proceed by simulating such data for bond-dependent "test cases" on triangular and honeycomb lattices . I show that each nearest-neighbor interaction has a distinct signature in magnetic diffuse-scattering data, and that such data contain sufficient information to determine the spin Hamiltonian unambiguously viaunconstrained fits . Remarkably, powder-averaged data retain some sensitivity to bond-dependent interactions, and can constrain them when single-crystal samples are unavailable.
I demonstrate applications of this approach to experimental data for the triangular-lattice quantum spin-liquid candidate YbMgGaO4  and the candidate Kitaev honeycomb material NaNi2BiO6–δ (δ = 0.33) . I conclude by discussing its advantages and limitations in the context of developments in reverse Monte Carlo refinement, pair distribution function analysis, and machine learning.
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 Broholm et al., Science 367, eaay0668 (2020).
 Laurell & Okamoto, npj Quantum Mater. 5, 2 (2020).
 Chaloupka & Khaliullin, Phys. Rev. B 92, 024413 (2015).
 Paddison, Phys. Rev. Lett. (in press). arXiv:2002.12894 (2020).
 Paddison et al., Nat. Phys. 13, 117–122 (2017).
 Scheie et al., Phys. Rev. B 100, 214421 (2019).
*Laboratory Directed Research and Development Program of Oak Ridge National Laboratory.
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