=1/2 distorted kagome Hamiltonians in titanium fluorides

We determine the connection between highly frustrated kagome based Hamiltonians and a recently synthesized family of materials containing Ti³⁺ S = 1/2 ions [1]. With the help of a combination of all electron density functional theory and numerical diagonalization techniques, we establish the Heisenberg Hamiltonians for the distorted kagome antiferromagnets Rb₂NaTi₃F₁₂, Cs₂NaTi₃F₁₂, and Cs₂KTi₃F₁₂. We determine magnetization curves in excellent agreement with experimental observations. Our calculations successfully clarify the relationship between the experimental observations and the magnetization-plateau behavior at 1/3 height of the saturation and predict characteristic behaviors under fields that are higher than the experimentally measured region. We demonstrate that the studied Ti(III) family of materials interpolates between the kagome strip and kagome lattice. Further members of this family of materials are also considered.

[1] H. O. Jeschke, H. Nakano and T. Sakai, Phys. Rev. B 99, 140410(R) (2019).