Abstract
The spin ice materials and are by now perhaps the best-studied classical frustrated magnets. A crucial step towards the understanding of their low temperature behavior—both regarding their unusual dynamical properties and the possibility of observing their quantum coherent time evolution—is a quantitative understanding of the spin-flip processes which underpin the hopping of magnetic monopoles. We attack this problem in the framework of a quantum treatment of a single-ion subject to the crystal, exchange, and dipolar fields from neighboring ions. By studying the fundamental quantum mechanical mechanisms, we discover a bimodal distribution of hopping rates that depends on the local spin configuration, in broad agreement with rates extracted from experiment. Applying the same analysis to and , we find an even more pronounced separation of timescales signaling the likelihood of coherent many-body dynamics.
- Received 6 November 2018
- Revised 20 March 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.067204
© 2019 American Physical Society