The minimal spin Hamiltonian of alpha-RuCl3 · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
The minimal spin Hamiltonian of $\alpha$-RuCl3
Plain
Interpreting any $\alpha$-RuCl3 experiment requires its spin couplings, yet published fits disagree even on which coupling is largest. Without an agreed set, claims of spin-liquid behavior cannot be checked against theory.
Precise · changed · core
Revision 1: Determine the exchange constants of alpha-RuCl3 in H = sum over nearest-neighbor bonds <ij> of type gamma of [J S_i . S_j + K S^gamma_i S^gamma_j + Gamma (S^alpha_i S^beta_j + S^beta_i S^alpha_j) + Gamma' (terms mixing gamma with alpha and beta)] + J3 sum over third neighbors of S_i . S_j, with $(\alpha, \beta, \gamma)$ a permutation of $(x, y, z)$, from a joint fit of inelastic neutron spectra, THz and ESR modes, the field-angle dependence of the critical field and the high-field magnon spectrum. An answer is one parameter set with error bars consistent with all these data, including the sign of $K$ and the ratio $K/\Gamma$.
Revision 2: Determine the exchange constants of alpha-RuCl3 in $H = \sum$ over nearest-neighbor bonds $\langle ij\rangle$ of type $\gamma$ of [$J S_i . S_j + K S^{\gamma}_{i} S^{\gamma}_{j} + \Gamma (S^{\alpha}_{i} S^{\beta}_{j} + S^{\beta}_{i} S^{\alpha}_{j}) + \Gamma'$ (terms mixing $\gamma$ with $\alpha$ and $\beta$)] $+ J3 \sum$ over third neighbors of $S_i . S_j$, with $(\alpha, \beta, \gamma)$ a permutation of $(x, y, z)$, from a joint fit of inelastic neutron spectra, THz and ESR modes, the field-angle dependence of the critical field and the high-field magnon spectrum. An answer is one parameter set with error bars consistent with all these data, including the sign of $K$ and the ratio $K/\Gamma$.
Settled by
A global fit of neutron, THz, ESR, magnetization and magnetostriction data using quantum many-body (beyond linear spin-wave) calculations of the spectra that yields a unique parameter set.
Kind
well-posed
Answer type
value
References
(empty)
Literature status
contested
Status note
Proposed parameter sets range from Kitaev dominated to regions with a large off-diagonal $\Gamma$ term; Maksimov and Chernyshev (Physical Review Research 2020) argued for the latter.
Posed since
(empty)

Decisions