Abstract
The spinel undergoes a transition into a dimerized state at low temperatures that is expected to be a spin singlet. However, no signature of a singlet-triplet transition has been discovered, in part due to the difficulty of predicting the energy of the transition from theory. We find that the dimers of can be described by a Heisenberg model with very small interactions between different dimers. Using high-accuracy first-principles quantum Monte Carlo combined with a model-fitting approach, we predict the singlet-triplet gap of these dimers to be 350(50) meV, a higher energy than previous experimental observations have considered. The prediction is published in advance of experimental confirmation.
- Received 21 November 2018
- Revised 7 February 2019
DOI:https://doi.org/10.1103/PhysRevB.99.081118
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