Abstract
What is the correct low-energy spin Hamiltonian description of α-RuCl3? The material is a promising Kitaev spin liquid candidate, but is also known to order magnetically, the description of which necessitates additional interaction terms. The nature of these interactions, their magnitudes and even signs, remain an open question. In this work we systematically investigate dynamical and thermodynamic magnetic properties of proposed effective Hamiltonians. We calculate zero-temperature inelastic neutron scattering (INS) intensities using exact diagonalization, and magnetic specific heat using a thermal pure quantum states method. We find that no single current model satisfactorily explains all observed phenomena of α-RuCl3. In particular, we find that Hamiltonians derived from first principles can capture the experimentally observed high-temperature peak in the magnetic specific heat, while overestimating the magnon energy at the zone center. In contrast, other models reproduce important features of the INS data, but do not adequately describe the magnetic specific heat. To address this discrepancy we propose a modified ab initio model that is consistent with both magnetic specific heat and low-energy features of INS data.
| Original language | English |
|---|---|
| Article number | 2 |
| Journal | npj Quantum Materials |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2020 |
Funding
We thank C. Balz, A. Banerjee, T. Berlijn, S. E. Nagler, A. M. Samarakoon, and D. A. Tennant for helpful discussions, and A. Loidl for providing the magnetic specific data. We thank Y. Yamaji both for useful discussions and assistance with HΦ. The research by P.L. and S.O. was supported by the Scientific Discovery through Advanced Computing (SciDAC) program funded by the US Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences, Division of Materials Sciences and Engineering. This research used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract DE-AC05-00OR22725, and of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is managed by UT-Battelle and supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. An award of computer time was provided by the INCITE program. A portion of the work was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.