Role of Hydrogen in the Spin-Orbital-Entangled Quantum Liquid Candidate H3LiIr2O6

Abstract

Motivated by recent reports of H3LiIr2O6 as a spin-orbital-entangled quantum liquid, we investigate via a combination of density functional theory and non-perturbative exact diagonalization the microscopic nature of its magnetic interactions. We find that while the interlayer O-H-O bond geometry strongly affects the local magnetic couplings, these bonds are likely to remain symmetrical due to large zero-point fluctuations of the H positions. In this case, the estimated magnetic model lies close to the classical tricritical point between ferromagnetic, zigzag and incommensurate spiral orders, what may contribute to the lack of magnetic ordering. However, we also find that substitution of H by D (deuterium) as well as disorder-induced inhomogeneities destabilize the O-H/D-O bonds modifying strongly the local magnetic couplings. These results suggest that the magnetic response in H3LiIr2O6 is likely sensitive to both the stoichiometry and microstructure of the samples and emphasize the importance of a careful treatment of hydrogen for similar systems. arXiv:1807.02124v2 [cond-mat.str-el]

Strong Effect of Hydrogen Order on Magnetic Kitaev Interactions in H3LiIr2OYadav1, Ray2, Eldeeb3 et al. 2018Phys. Rev. Lett.584370View full textAdd to dashboardCite

“…Note: After finalizing this manuscript we became aware of other computational study on H 3 LiIr 2 O 6 using a combination of DFT and non-perturbative ED [44]. The effective magnetic couplings and the trends induced by disorder that are reported in that investigation are consistent with our findings.…”

Unusual spin dynamics in the low-temperature magnetically ordered state of Ag3LiIr2O6

“…Theoretical ab initio calculations have also shown for these systems that although the bond-dependent Kitaev interactions are significant, the Heisenberg and other non-Kitaev terms are not negligible. It has been suggested that these systems lie close to the tricritical point between ferromagnetic, zigzag, and incommensurate spiral order resulting in the absence of magnetic order [18]. Calculations further reveal that the interlayer O-H-O geometry as well as lack of hydrogen order also strongly influence the Kitaev and other exchange interactions having strong impact on its magnetic properties [18,19].…”

Anderson–Kitaev spin liquid

“…However, it is also known that these honeycomb materials cannot fully be understood by the original (pure) Kitaev model 12,13 . While other diagonal or offdiagonal interactions might be important in real materials 14 , the importance of disorder has been ignored in these materials until recently [15][16][17] . Indeed, experiments in A 3 LiIr 2 O 6 (A = H, Ag, etc.)…”